Add getDiscoveredHeartManDevices() to HeartManDiscovery

This method returns the list of the previously by
discoverHeartManDevices() discovered devices.
Remove IByteListener and Recorder

Since recording plain bytes is not used anymore, those obsolete classes
are removed.

This closes #1
Remove RandomHeartManMock

This was previously introduced for testing, but is not needed anymore.
Remove HeartManInputStream

This InputStream is not used anymore since the byte[]-to-short
conversion from the Bluetooth stream is now handled in the
ListeningTask.