refactoring of the mavlink connection class structure.
Several core utilities not dependant on android were moved to 'Core'.
The restructuring should also fix a persistently annoying 'save to log' bug, which i think might have been the result of a race condition.
bug fixes.
bug fixes.
Merge branch 'master' of https://github.com/DroidPlanner/droidplanner into fix_savetolog_bug

Conflicts:
	Android/src/org/droidplanner/android/maps/providers/google_map/GoogleMapFragment.java
bug fixes.
Merge branch 'master' of https://github.com/DroidPlanner/droidplanner into fix_savetolog_bug
Merge branch 'master' of https://github.com/DroidPlanner/droidplanner into fix_savetolog_bug

Conflicts:
	Android/src/org/droidplanner/android/fragments/DroneMap.java
Merge branch 'master' of https://github.com/DroidPlanner/droidplanner into fix_savetolog_bug
Merge branch 'master' of https://github.com/DroidPlanner/droidplanner into fix_savetolog_bug
moved 'imminent collision' state from the drone `State` to its `Altitude`.
Merge pull request #1031 from ne0fhyk/cleanup_crash_alert

Moved 'imminent collision' state
Merge branch 'master' of https://github.com/DroidPlanner/droidplanner into feature_android_lib
improved Google map implementation.
Merge pull request #1009 from ne0fhyk/fix_savetolog_bug

MavLink Connection restructuring
updated the `NotificationProvider` interface.
Merge branch 'master' of https://github.com/DroidPlanner/droidplanner into feature_android_lib
Merge branch 'feature_android_lib' of https://github.com/ne0fhyk/droidplanner into feature_android_wear

Conflicts:
	Android/src/org/droidplanner/android/communication/MAVLinkClient.java
	Android/src/org/droidplanner/android/communication/connection/MAVLinkConnection.java
	Android/src/org/droidplanner/android/maps/providers/google_map/GoogleMapFragment.java
	Android/src/org/droidplanner/android/notifications/EmergencyBeepNotificationProvider.java
	Android/src/org/droidplanner/android/notifications/StatusBarNotificationProvider.java
	Android/src/org/droidplanner/android/services/MAVLinkService.java