added heartbeat timeout event.
addition of several drone events.
Merge branch 'master' of github.com:ne0fhyk/3DR-Services-Library

Conflicts:
	Libraries/3DR-Services-Library/lib/src/com/ox3dr/services/android/lib/drone/event/Event.java
Merge branch 'master' of github.com:ne0fhyk/3DR-Services-Library
bug fixes.