am 4570dfa2: am 7b0463a9: am ed2a70d6: docs: add the Bluetooth developer guide, and make some revisions to the BT javadocs

Merge commit '4570dfa2016fa32b6f7b29aabadb9d708482b94d'

* commit '4570dfa2016fa32b6f7b29aabadb9d708482b94d':
  docs: add the Bluetooth developer guide,