Add setMuteState to webrtc object.
Add buttons for audio mute/unmute and improve general style handling of the call control buttons
Add functionality for the audio mute toggle button
Fix whitespace
Stop the outgoing sound when a call is established
Fix review comments - tidy html
Merge pull request #168 from Standard8/fix_outgoing

Stop the outgoing sound when a call is established
Merge pull request #165 from Standard8/audio_mute

Add an audio mute button