Implemented Phone call interruption logic. Reset audio on interruption began and reverting back on interruption ended.
The call interruption logic works ok if you decline a call.
On accepting a call, the interruption end notification is called sometimes, sometimes a thread kill message is thrown by OT SDK. Have to work more on this
Also added a detectCurrent audio route utility methods
Added bunch of const strings for audio route change inputs.
added debug message if phone speakers is in use
added comments to changing audio route
check in
Merge branch 'develop' of https://github.com/SteveMcFarlin/opentok-ios-sdk-samples into develop

Conflicts:
	6.External-Audio-Device/External-Audio-Device/MyAudioDevice.m
Merge pull request #4 from JayTokBox/develop

Merged with Steve's branch