move duplicate code from WavAdapter and FlacAdapter to a base class

fix Promise in setMuted

When newly joined clients register for XMPP events upon
CONFERENCE_JOINED, those events that is carried by presence (e.g. START_COMMAND) was
already fired.
Temporary solution is to let the client send a ping message after
registering XMPP event listeners. The moderator will respond with
pong, which forces the presence to be resent.

Situation when the RecordingController receives a new START_COMMAND
while it is initializing the recording adapter for the previous
START_COMMAND.

index.js of local recording

local-recording(ui): recording button

local-recording(encoding): flac support with libflac.js

Fixes in RecordingController; integration with UI

local-recording(controller): coordinate recording on different clients

local-recording(controller): allow recording on remote participants

local-recording(controller): global singleton

local-recording(controller): use middleware to init LocalRecording

cleanup and documentation in RecordingController

local-recording(refactor): "Delegate" -> "Adapter"

code style

stop eslint and flow from complaining

temp save: client status

fix linter issues

fix some docs; remove global LocalRecording instance

use node.js packaging for libflac.js; remove vendor/ folder

code style: flacEncodeWorker.js

use moment.js to do time diff

remove the use of console.log

code style: flac related files

remove excessive empty lines; and more docs

remove the use of clockTick for UI updates

initalize flacEncodeWorker properly, to avoid premature audio data transmission

move the realization of recordingController events
from LocalRecordingButton to middleware

i18n strings

minor markup changes in LocalRecordingInfoDialog

fix documentation