Create a reference to the jquery element instead of querying for
it globally. This is to better encapsulate the small video
component.

This better mimics declarative jsx.

The local audio stream is attached to an audio element that is
always muted. As such, local audio is not being rendered and
the attaching may just not be needed at all.

This would better mimic React behavior where each component has
its own markup, instead of relying on markup existing elsewhere.

When do we need tracks?

- Welcome page (only the video track)
- Conference (depends if starting with audio / video muted is requested)

When do we need to destroy the tracks?

- When we are not in a conference and there is no welcome page

In order to accommodate all the above use cases, a new component is introduced:
BlankWelcomePage. Its purpose is to take the place of the welcome page when it
is disabled. When this component is mounted local tracks are destroyed.

Analogously, a video track is created when the (real) welcome page is created,
and all the desired tracks are created then the Conference component is created.
What are desired tracks? These are the tracks we'd like to use for the
conference that is about to happen. By default both audio and video are desired.
It's possible, however, the user requested to start the call with no
video/audio, in which case it's muted in base/media and a track is not created.

The first time the app starts (with the welcome page) it will request permission
for video only, since there is no need for audio in the welcome page. Later,
when a conference is joined permission for audio will be requested when an audio
track is to be created. The audio track is not destroyed when the conference
ends. Yours truly thinks this is not needed since it's a stopped track which is
not using system resources.

This is only desired when the unmuting action took place due to a manual user
intervention or the audio-only mode being disengaged.

The current custom debounce function sets a timeout and ensures
additional calls are not executed while the timeout is pending.
Regulating the call of a function while also ensuring it gets
called at a certain time is a throttle.

The name better suits its purpose, since it can be called at any time.

Iterate over objects and copy over primitives and arrays
instead of using _.merge, as merge will not replace a config
entry completely. For arrays in a target object, the arrays
will have its indices replaced. This means if a source array
is empty, the target array will be left alone. Similarly,
if the target array is longer than a source array, there
will be indices not touched in the target array.

* ref: video muted state

Get rid of 'videoMuted' flag in conference.js

* ref: audio muted state

Get rid of 'audioMuted' flag in conference.js

* fix(conference.js|API): early audio/video muted updates

* ref(conference.js): rename isVideoMuted

Rename isVideoMuted to isLocalVideoMuted to be consistent with
isLocalAudioMuted.

* doc|style(conference.js): comments and space after if

* ref: move 'setTrackMuted' to functions

* fix(tracks/middleware): no-lonely-if

* ref(features/toolbox): get rid of last argument

* ref(defaultToolbarButtons): rename var

- Remove non-redux paths for hiding and showing remote videos.
- Hook web filmstrip to redux to know when to hide remote videos.
  This works, even though VideoLayout is handling RemoteVideo
  appending, because react is only monitoring filmstrip's declared
  JSX which does not change except for attributes (css classes).

Deep/universal linking now utilizes loadURL (when possible). But loadURL
is imperative in the native source code while its JavaScript counterpart
i.e. React App Component prop url is declarative. So there's the
following bug: open a URL, leave the conference (by tapping the hangup
button, for example), and then opening the same URL actually leaves you
on the Welcome page (if enabled; otherwise, a black screen).

The implementation has a flow though: opening the same URL twice in a
row without an intervening leave will leave the first opening and join
the new opening. Which can be improved by not leaving and joining if the
conference is joined, joining, an not leaving. But that can be done
separately as an improvement independent of the current implementation
details.

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.

* fix(quality-slider): prevent resizing by making p2p warning hidden

Instead of removing and appending the p2p warning, make it always
appended but toggle visibility so it always takes up space. This
should prevent resizing when the warning appears. Margin and
padding were adjusted to account for the empty space displayed
by a hidden p2p warning.

* let vertical size change

* ref(invite): use AtlasKit for invite modal buttons and inputs

- Convert button to AK Button.
- Convert inputs to AK FieldText.

* remove noop, replace with custom empty func

This will prevent the quality dialog from closing when changing
desired quality level.

With AtlasKit InlineDialog, the filmstrip z-index in vertical
filmstrip mode was adjusted as it had to be set to fixed position
for the dialogs to automagically be position fixed. This left
behind a regression where the filmstrip z-index was the same as
the video quality label, but came later in the dom, so the label
was not clickable. This commit modifies the z-index of the
vertical filmstrip to account for clicking of the video quality
label.