Bluetooth SCO States

[rwrz]

I've been working on a Bluetooth solution and also a way to choose the current selected output. So I've tested a few methods and also exposed bluetooth audio states, to track connection status (since the startBluetoothSco isn't enough to consider a successful switch to bluetooth).

Commit log:

• exposed bluetooth audio states, so we can track if it is connected/disconnected
• tested startBluetoothSco|stopBluetoothSco|setBluetoothScoOn
• tested setCommunicationDevice|getCommunicationDevice|clearCommunicationDevice
• tested setStreamVolume
• linting AndroidAudioManager

[ryanheise]

I have fixed the spacing to be consistent with the rest of the code, and also made some minor alterations to the Dart-side API design. The "State" class was renamed to just "Event", and the "States" class was renamed to "State" since classes are typically named after the singular. Also, I have removed the getter for the current event, since only states (and not events) should be queryable. Those changes have been merged into master.

Let me know if you find anything more that needs to be changed before I release, otherwise I'll proceed with the release.

[rwrz]

Perfect and sorry again for messing up with the formatting.

[ryanheise]

This has now been published as 0.1.12 - thank you for contributing!