Previously, the DeviceCommunicationService was invoked directly,
via
Intent intent = new Intent(foo, bar);
intent.setExtra(EXTRA_BAZ, baz);
startService(...);
and this was scattered throughout GadgetBridge.
Now there is a "frontend" available, so that you can call
the service more easily, like
GBApplication.deviceService().connect();
For a start, this client interface (DeviceService) actually
implements the same interface (EventHandler) as the receiving side
(DeviceSupport). This may change in the future.
This will also make testing much easier, because we can use
this client interface to invoke the test service as well.
