Working on QGraphicsView-based local waypoints interface supporting drag-and-drop, commented code, fixed Google Maps interface, added mouse and SpinBox zoom to HSIWidget, fixed MAV-based coloring and stylesheets - MEGA COMMIT

Cleaned up and commented major code parts. Refactoring HDD and HSI widgets to support QGraphicsView drag-and-drop, tested multi-MAV support more intensely, currently adding the system coloring to all widgets

Significantly improved plotting, now capturing data in linechart allows limmediate processing / analysis of the whole flight

Continue the scaffoldinf for the WP click creation. Now the waypoints are graphically shown in the MapControl. Ready to start interacting with the Waypoint widget

Cleaned up communication structure significantly, should now be easier to add new links. Signal bytesReceived(link, QByteArray) is now only way to pass on newly received data

Finished scaffolding the graphical addition of WP via the MapWidget. Added the possibility to display the latitude and longitude of the cursor as a property of QMapControl. Major reorganization of the MapWidget constructor

Major refactoring of the waypoint code. The new design fits the model-view-controller pattern better.

Added MAVLinkLight as an example how to add new protocols, it is currently not an actual implemented protocol

(cherry picked from commit c3194971)