For the most part the changes are taking the "static propTypes" declaration off
of components and declaring them as Flow types. Sometimes to support flow some
method signatures had to be added. There are some exceptions in which more had
to be done to tame the beast:
- AbstractVideoTrack: put in additional truthy checks for videoTrack.
- Video: add truthy checks for the _videoElement ref.
- shouldRenderVideoTrack function: Some component could pass null for the
  videoTrack argument and Flow wanted that called out explicitly.
- DisplayName: Add a truthy check for the input ref before acting on it.
- NumbersList: Move array checks inline for Flow to comprehend array methods
  could be called. Add type checks in the Object.entries loop as the value is
  assumed to be a mixed type by Flow.
- AbstractToolbarButton: add additional truthy check for passed in type.

* fix(connection): reload immediately on possible split-brain

There isn't an explicit way to know when a split brain
scenario has happened. It is assumed it arises when an
"item-not-found" connection error is encountered early
on in the conference. So, store when a connection has
happened so it be calculated how much time has
elapsed and if the threshold has not been exceeded
then do an immediate reload of the app instead of
showing the overlay with a reload timer.

* squash: rename isItemNotFoundError -> isShardChangedError

Adds a fatal error state on which will depend whether or not the reload
screen is to be displayed. It is to happen when a relevant fatal error
action is not claimed by any feature for error recovery (the recoverable
flag is not set).

Turns out React Native offers an object with the following definition:

{
    bottom: 0,
    left: 0,
    position: 'absolute',
    right: 0,
    top: 0
}

* Handles connection failed event details (passing them to analytics).

* Fixing comments.

* Updates depending versions to be able to test.

* Fixing comments.

* Fixes wrong jsdoc.

* ref: Restructures the pinned/unpinned events.

* ref: Refactors the "audio only disabled" event.

* ref: Refactors the "stream switch delay" event.

* ref: Refactors the "select participant failed" event.

* ref: Refactors the "initially muted" events.

* ref: Refactors the screen sharing started/stopped events.

* ref: Restructures the "device list changed" events.

* ref: Restructures the "shared video" events.

* ref: Restructures the "start muted" events.

* ref: Restructures the "start audio only" event.

* ref: Restructures the "sync track state" event.

* ref: Restructures the "callkit" events.

* ref: Restructures the "replace track".

* ref: Restructures keyboard shortcuts events.

* ref: Restructures most of the toolbar events.

* ref: Refactors the API events.

* ref: Restructures the video quality, profile button and invite dialog events.

* ref: Refactors the "device changed" events.

* ref: Refactors the page reload event.

* ref: Removes an unused function.

* ref: Removes a method which is needlessly exposed under a different name.

* ref: Refactors the events from the remote video menu.

* ref: Refactors the events from the profile pane.

* ref: Restructures the recording-related events.

Removes events fired when recording with something other than jibri
(which isn't currently supported anyway).

* ref: Cleans up AnalyticsEvents.js.

* ref: Removes an unused function and adds documentation.

* feat: Adds events for all API calls.

* fix: Addresses feedback.

* fix: Brings back mistakenly removed code.

* fix: Simplifies code and fixes a bug in toggleFilmstrip

when the 'visible' parameter is defined.

* feat: Removes the resolution change application log.

* ref: Uses consistent naming for events' attributes.

Uses "_" as a separator instead of camel case or ".".

* ref: Don't add the user agent and conference name

as permanent properties. The library does this on its own now.

* ref: Adapts the GA handler to changes in lib-jitsi-meet.

* ref: Removes unused fields from the analytics handler initializaiton.

* ref: Renames the google analytics file and add docs.

* fix: Fixes the push-to-talk events and logs.

* npm: Updates lib-jitsi-meet to 515374c8d3.

* fix: Fixes a recently introduced bug in the google analytics handler.

* ref: Uses "value" instead of "delay" since this is friendlier to GA.

They will be stored in redux and the PageReloadOverlay will be displayed.

Note that this commit also introduces a subtle (and yet important!) change:
the location URL is now always set, regardless of the configuration loading or
not. This is needed in order for the retry logic to pick it up.

It's not supposed to go on top of everything, like an error would. It's tied to
a conference, so render it outside of the OverlayContainer.

* ref(analytics): centralize all event names

* squash: fix typo and alpha ordering

* squash: rename file to AnalyticsEvents to parallel lib-jitsi-meet

These modification are not necessarily directly related to the
containing PR, I merely saw them while reviewing the containing PR.

Do the selection in mapStateToProps so the container itself doesn't need to
receive all the props that each overlay needs.

Each overlay is responsible for fetching their own props and for providing a
"needsDisplay" static method wich will be called with the full redux state and
should return true if the overlay needs displaying.

Also eliminate duplicated state keeping: the connection and conference error
states can be fetched from their respective base features.

Prepares for the latest eslint & flow-related npm packages which cause
these errors.

ESLint 4.8.0 discovers a lot of error related to formatting. While I
tried to fix as many of them as possible, a portion of them actually go
against our coding style. In such a case, I've disabled the indent rule
which effectively leaves it as it was before ESLint 4.8.0.

Additionally, remove jshint because it's becoming a nuisance with its
lack of understanding of ES2015+.

* Javadoc introduced @code as a replacement of <code> and <tt> which is
  better aligned with other javadoc tags such as @link. Use it in the
  Java source code. If we switch to Kotlin, then we'll definitely use
  Markdown.

* There are more uses of @code in the JavaScript source code than <tt>
  so use @code for the sake of consistency. Eventually, I'd rather we
  switch to Markdown because it's easier on my eyes.

* Xcode is plain confused by @code and @link. The Internet says that
  Xcode supports the backquote character to denote the beginning and end
  of a string of characters which should be formatted for display as
  code but it doesn't work for me. <tt> is not rendered at all. So use
  the backquote which is rendered itself. Hopefully, if we switch to
  Markdown, then it'll be common between JavaScript and Objective-C
  source code.

Prepare for React 16.

Gradually, we exploded the error of CONNECTION_FAILED in multiple
redux state properties. The explosion makes maintenance harder because
the properties have to be updated in sync. Collect them in an object
resembling an Error instance.

The functions need not return anything, or it will be dispatched as another
action.

Rewrite the non-React RingOverlay into the React Component CallOverlay
in a way which makes it easier to port to React Native.

There were getDomain, setDomain, SET_DOMAIN, setRoomURL, SET_ROOM_URL
which together were repeating one and the same information and in the
case of the 'room URL' abstraction was not 100% accurate because it
would exist even when there was no room. Replace them all with a
'location URL' abstraction which exists with or without a room.

Then the 'room URL' abstraction was not used in (mobile) feature
share-room. Use the 'location URL' there now.

Finally, removes source code duplication in supporting the Web
application context root.

Rename setStateProperties and setStateProperty to assign and set,
respectively. Inspired by Object.assign, _.assign, and _.set.

We seemed to be using the names "film strip" and "filmstrip" (and,
consequently, their source code-conscious forms such as film-strip,
FilmStrip, etc.) In order to comply with our coding style which requires
a consistent one name for a given abstraction, choose one name and
rename the uses of the other name.

Wikipedia has a definition of a "filmstrip", I couldn't find a "film
strip". I guess our abstraction can be seen as what's described there.
When I google "film strip", I get results about "filmstrip" at the top.
That's why I chose "filmstrip".

Certain uses of "film strip" such as interfaceConfig.filmStripOnly and
in the external API I left untouched in an attempt to preserve
compatibility.

I wasn't sure whether CSS was tangled in compatibility so I made a
choice and renamed there was well.

In this case makes more sense to have overlay frame included in every overlay instead
of abstract class that implements the overlay frame and have to be extended by every
overlay. In addition, mapStateToProps isn't working well with inheritance.