Fixes crash on undefined var in case get user media was not called,
before the conference started.

* ref: Moves the deployment info variables to config.js

instead of using globals.

* feat: If configured, adds the user's region to presence.

* fix: Guards against accessing undefined properties,

and uses the crossRegion variable from the config.

* style: Fixes formatting.

Firefox's getUserMedia can take longer than 500ms to complete. This
causes the permission prompt timeout to fire even if the user has
given permission to audio and video. There may not be a reliable
way right now to check if the user has given permission to both
audio and video so dumbly increase the timeout instead.

Reorders JitsiTrackEvents.TRACK_AUDIO_LEVEL_CHANGED event arguments by
putting TraceablePeerConnection at the end. This way it's easier to
treat it as "library internal".

* move all local deployment properties into  window.jitsiAnalyticsPermanentProperties property
no longer need to set jitsiRegionInfo from external_connect, now set from Jitsi meet local.html, can be customized by deployment

* change to using shorter lines by extracting longer property name into a shorter local variable name

* changed to using more generic variable name jitsiDeploymentInfo after discussion with the team
added comment describing source of this variable

* feat: multiple, simultaneous RTP stats

Makes it possible to have remote RTP stats running for more than one
peerconnection at a time.

* feat(stats): report RTT all the time

Will report JVB RTT (and end to end) while in P2P mode and vice versa.

* fix(JitsiConferenceEvents): remove CONNECTION_STATS

CONNECTION_STATS event is no longer emitted.

* fix(AvgRTPStatsReported): users with no video

Do not include FPS == 0 in average remote FPS calculation. Report NaN
for local FPS when video muted or no video device. NaN will be reported
for avg remote FPS if no video is received.

* fix(AvgRTPStatsReported): reset total packet loss

* feat(AvgRTPStatsReported): report 'screen' FPS

Will report average FPS for screen videos separately from camera videos,
but only if available (camera video reports NaN FPS when not available).

* fix(AvgRTPStatsReported): end2endRTT

Needs to report JSON with value.

* feat(AVG RTP stats): separate audio and video bitrate

Will report average audio and video bitrates separately.

* doc(JitsiConference): try to improve comment

* fix(AvgRTPStatsReporter): remove confusing reset

There's no a clear reason for doing reset there.

* ref(AvgRTPStatsReporter): rename var

Webpack 2 defines module.exports as a read-only property in ES6 modules.

For audio previewing, some browsers cannot have multiple local
audio streams at once. For audio output previewing, local
stats need to be collected to detect changes in volume level.

Pull Request #435

* Adds peer connection statuses (active/inactive/interrupted/restoring).

The peer connection used to be check with is connection active. Adding new states like active, inactive, when the connection was intentionally stopped by the bridge, interrupted due to network problem and restoring, which is the state of a peer which was inactive as being out of lastN and is now entering lastM and eventually will become active.

* Adds timers to track restoring status.

If restoring too long we set the connection status to interrupted. We save timestamps for all participants entering lastN and set the status for the connection to restoring for 5 seconds, or till it goes into active or exits lastN.

* Adds initial connectionStatus of newly created participant - active.

* Fixes some jsdocs.

* Uses symbols for strings and use of map, fixing comments on PR.

* Removes symbols.

* Adds video sip gw handling.

Parsing presence and availability of the service. Adding possibility to start/stop a video sip gw session.

* Fix comments.

* Adds more jsdoc about create session and renames import to use the filename is imports.

Our JSHint configuration is not extensive and we have excluded multiple
files from linting. Additionally, we have seen JSHint to be unable to
parse newer ECMAScript features such as the object spread operator
(proposal).

On the other hand, we have seen ESLint to beautifully work on React and
React Native source code in addition to ES2015 and later. Introduce
ESLint alongside JSHint as an intermediate step to eventually switching
from JSHint to ESLint.

As our source code does not fully follow even the JSHint rules we have,
it is very difficult to introduce ESLint with many rules. At the
beginning, introduce it with as little rules as possible. Morever,
ESLint is able to automatically fix certain rule offenders so once we
have ESLint merged we can incrementally add new rules while keeping our
commits' modification on as little subjects as possible.