MidiManager: Address API Council feedback:

Rename MidiDeviceInfo.getPortList() to getPorts()

Rename MidiManager.getDeviceList() to getDevices()

Rename MidiReceiver.onReceive() to onSend()

Replace MidiManager.DeviceOpenCallback and BluetoothOpenCallback
with new interface MidiManager.OnDeviceOpenedListener

Add MidiSender.onConnect() and onDisconnect()

Add MidiReceiver.onFlush()

Ensure that MidiReceiver max message size is immutable

Bug: 21044677
Change-Id: I7711734a45e831e9744849a6f569e906feff9f80