As https://facebook.github.io/react/docs/typechecking-with-proptypes.html
says, React.PropTypes have moved into the npm package prop-types since
React v15.5. I've already failed to update certain devDependencies
because they mandate the use of prop-types so I'd rather we (gradually
at least) move to prop-types rather than face a lot of work later on.

Avatars are cached to the filesystem and loaded from there when requested again.
The cache is cleaned after a conference ends and on application startup
(defensive move).

In addition, implement a fully local avatar system, which is used as a fallback
when loading a remote avatar fails. It can also be forced using a prop.

The fully local avatars use a user icon as a mask and apply a background color
qhich is picked by hashing the URI passed to the avatar. If no URI is passed a
random color is chosen.

A grace period of 1 second is also implemented so a default local avatar will be
rendered if an Avatar component is mounted but has no URI. If a URI is specified
later on, it will be loaded and displayed. In case loading the remote avatar
fails, the locally generated one will be used.

- Create a notification component for displaying a toggle.
- Create an action for showing the component if allowed by
  the local storage setting and for saving the setting to
  local storage.
- Remove all notifications having a timeout by default so the
  device error notification must be dismissed manually.
- Split the camera and mic error dialog into two separate
  notifications.

* feat(notifications): implement a react/redux notification system

* squash into impl explicit timeout, style

* ref(notifications): convert toastr notifications to use react

* ref(toastr): remove library

* squash into conversion: pass timeout

* squash into clean remove from debian patch

Our fixes have been applied upstream and a release has been made.

* Fix(AddPeopleDialog): Fixes error state and close dialog

* (to-squash) Addresses comments

Apparently iOS doesn't like dangling background tasks very much, so update the
background timers plugin with a version which fixes this.

https://github.com/ocetnik/react-native-background-timer/pull/38

Also accomodate for the API changes upstream.

Credits to @lyubomir for finding the needle in the haystack.

The functionality around logging including logging_config.js i.e.
loggingConfig and the other classes and/or functions that initialize
loggers for Jits Meet truly deserves a feature of its own. Start getting
in that direction on both Web and mobile by introducing
features/base/logging and bringing loggingConfig to mobile.

AtlasKit Dropdown was recently updated to support fitting the
width of its container. However, AtlasKit Button, the trigger
element currently used for the dropdowns, does not fit the width
of AtlasKit Dropdown and stll has text overflowing out of its
button when there is an iconBefore prop passed in. Instead of
using AtlasKit Button, use a div and mimic the button look. This
allows the "button" to fit the container width and can display
ellipsized text within itself.

Instead of using AtlasKit Single-Select, use Dropdown. Dropdown
differs in that an icon can be specified for the trigger element,
whereas Single-Select currently supports icons for all elements,
and Dropdown can show all options incuding the already-selected
option.

This change does introduce the issue of the trigger element not
taking up 100% width of the parent. Supporting such would involve
overriding AtlasKit CSS. The compromise made here was to do a
generic override of max-width so the trigger elements at least
stay within the parent and aligning the trigger elements to the
right.

The Device Selection modal consists of:
- DeviceSelection, an overly smart component responsible for
  triggering stream creation and cleanup.
- DeviceSelector for selector elements.
- VideoInputPreview for displaying a video preview.
- AudioInputPreview for displaying a volume meter.
- AudioOutputPreview for a test sound output link.

Store changes include is primarily storing the list of
available devices in redux. Other app state has been left
alone for future refactoring.

babel does not modify existing builtins by default. That means
some newer methods, such as Array.prototype.includes, may not
be available unless babel-polyfill is used.

It's no longer needed for building since Node >= 6 already has the minimum
required ES6 syntax. In addition, drop it from app.js since we use Webpack with
the Babel loader to transpile ES5 to ES6.

@atlaskit components will all require styled-components in the
future. Including it now will remove the unmet peer
dependency warning during npm install and prevent future build
breakages that might occur from using a new @atlaskit component
that requires it.

Pull Request #1449

#1411

Split language detectors to be web/native dependent. Take care of strings that contain html.

Adds translate function with default namespaces and options.

Recently expose-loader broke us when it updated from 0.7.1 to 0.7.2 and
we decided to stick to exact versions.

Turns out React Native's timers (setTimeout / setInterval) don't run while the
app is in the background: https://github.com/facebook/react-native/issues/167

This patch replaces the global timer functions with those from the
react-native-background-timer package, which work in the background.

These timers won't magically make an application work in the background, but
they will run if an application already happens to run in the background. That's
our case while in a conference, so these timers will run, allowing XMPP pings to
be sent and the conference to stay up as long as the user desires.

0.7.2 causes a ReferenceError: jQuery is not defined in autosize.

- Use 1 name for 1 abstraction. Instead of useFullScreen and enabled use
  fullScreen.
- Comments are correct English sentences so no double spaces between
  senteces, no capitalization of the work On midsentence.
- Write as little source code as possible if readability is preserved.
- Utilize Facebook's Flow.
- The name of a private function must start with _ and the jsdoc should
  state that the function is private.

The implementation varies across platforms, with the same goal: allow the app to
use the entire screen real state while in a conference.

On Android we use immersive mode, which  will hide the status and navigation bars.

https://developer.android.com/training/system-ui/immersive.html

On iOS the status bar is hidden, with a slide effect.