Replace 9 seperate valueChanged() signals with just 1, and remove the resultant tons of code duplication

Removed some dead code.
Added more valueChanged() signals to account for every data type. This moves the conversion over into the valueChanged receivers, which while it will require more slot-functions, makes it easier to add more code as any necessary conversion is done internally to the slot and so the signaler doesn't need to know the details.
I also added some more details on the types of units expected by valueChanged().

Fixed some destructor commands

Fixed roll angle in Google earth, still not smooth. Fixed a number of threading issues. Fixed all custom widget related bugs. Improved MAVLink decoder. Reduced CPU usage substantially across all views

Made MAVLink parser aware of line breaks in comments, added new servo output packet to QGC and simulation, enabled servo output display in new Actuator View (previous Payload view)

Added not yet working version of logging / log replay, fixed ALL bugs in main window, enabled full persistence in main window and serial link.

Added new options for windows serial port, fixed a number of bugs, added customizing options to instrument widgets

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

Major cleanup of MainWindow constructor. All widgets have now the visible property set to false on its constructor

Added support for MAVLink XML inclusion, added support for multiple Autopilots, improved protocol generation

Pushed parameter interface forward, now receiving of onboard params works, working on display and writing