Implemented audio route change logic with following priority, Bluetooth....

... Headset and Speakers

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.