* Regardless of whether the SDK client/consumer employs
  JitsiMeetActivity or JitsiMeetView, default to finishing the
  associated Activity upon invoking the back button (which is what
  Activity#onBackPressed() is documented to do).

* Do not break the public API of JitsiMeetView and, thus, Jitsi Meet SDK
  for Android.

If the JS side chooses to not handle the back button press call
'super.onBackPressed()' to close the app.

* feat(AddPeopleDialog): invite rooms

Distinguish between 'user' and 'videosipgw' search result items and
invite them with using different method.

* squash: fix typo in AddPeopleDialog.web.js

It will replace the "Join" text button while appNavigate lasts.

Note about the implementation: when appNavigate completes the component
may have been unmounted and thus we cannot touch its state. In order to
avoid this problem I added a 'mounted' instance variable which gets set
and reset in componentWillMount / Unmount respectively. This is to avoid
using isMounted, which is highly discouraged.

The basic indicator is extracted into a LoadingIndicator component,
which then NetworkActivityIndicator displays (or not) based on network
activity.

In order to support XMPP authentication, we'll need the message
accompanying the error and carried by lib-jitsi-meet's
CONFERENCE_FAILED in the redux store. We already carry the message in
the redux action and we've got the error in the redux store.

fix(Filmstrip.js): Make sure the local thumbnail is there

fix(conference.js): Add message listeners only when chat is enabled

In order to accommodate the requirements of the work on supporting XMPP
authentication on mobile/react-native, make dealing with Dialog a
little more generic and a little easier.

Without dominant speaker in redux, the wrong user will be
selected after an unpin event.

Filmstrip only mode displays a device selection dialog that
does not have access to the redux/connect. However, the current
VideoTrack extends from AbstractVideoTrack, which assumes a
redux connection. The fix is to move video display logic into
a separate component and have device selection use that, while
the existing VideoTrack remains connected to redux but
uses the new video display component.

Don't require autofocus because that prevents the app from appearing in
Google Play Store for some devices.

Don't require camera for the same reason but also because camera/video
is not a mandatory feature of the app, it's merely likely very
desirable.

In Chrome M63 a warning is shown, permissions won't be automatically allowed
afterwards. Reference:
https://sites.google.com/a/chromium.org/dev/Home/chromium-security/deprecating-permissions-in-cross-origin-iframes

Setting this early makes us future proof, while working with current versions
too: Chrome < 63 gives an error because it doesn't understand the option and
Firefox seems to ignore it, so both continue to work as before.

The class ReflectiveOperationException used in ExternalAPIModule was
introduced in API level 19.

Based on work authored by Shuai Li <sli@atlassian.com>, Daniel Ornelas
<dornelas@atlassian.com>, and Lyubo Marinov <lmarinov@atlassian.com>.

Instead of going through the Avatar object, call the getAvatarURL
directly so that the code flows consistently use the participant
representation within redux.

In certain scenarios we do need to import files instead of features but
even then it is our coding style to not write the file extension.

We broke external_api.min.js by importing react/features/util which
imported react/features/base/lib-jitsi-meet.

1. To reduce the risks of such a breakage until we add
   external_api.min.js to the torture tests, import as little as
   possible in modules/API/external/external_api.js.
2. Use the global JitsiMeetJS on Web in react/features/base/util.

JitsiMeetViewListener is an integral part of the public API of Jitsi
Meet SDK for Android. Utilize it in the Debug configuration of the Jitsi
Meet app for Android in order to increase (1) awareness of API breakages
and (2) API coverage.

The same goes for JitsiMeetViewDelegate in Jitsi Meet SDK and app for
iOS.