added mapbox provider dpmap implementation.
code cleanup.
increase features of the map interface.
cleaned up dp map interface.
Doesn't crash when can't access usb device.
Merge pull request #954 from squilter/issue_803

#803: Doesn't crash when can't access usb device.
Starting a new desktop GCS project
Decode incoming UDP traffic as MAVLink data
Implemented the MAVLink Handler to decode the messages.

Created a stub for the Handler class, to avoid null pointer exceptions on the heartbeat class
Removed dependency on Android Log class
Added an event parser for the Drone object
Removed initial test code
Implemented the send part of UDP

We now have two way communication.
Load the mission when detect the first heartbeat

This is only for debugging the two way communication.
Remove TAKEOFF from mission item fragment type list if there is more than 1 item in mission list
Allow LAND and RTL mission items to be set only in the end of mission list
Fix TAKEOFF item handling
Stop new mission items addition after RTL or LAND
Moved External libraries to Libraries folder
Importing jmapviewer library