Substantially bugfixed and improved deactivation/activation and persistence of widgets. A lot of testing of Google Earth view, only minor improvements

Fixed initial startup bugs, cleaned up the activation-deactivation of update timers. Added initial instructions for new users.

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

Pushed implementation of parameter settings, almost done. Added many new MAVLink messages needed for interaction with IMU

Improved runtime performance, currently hunting down a bug where the whole application gets repainted although only parts of it are refreshed