Added remote OpenGL drawing in 3D view. Any external application can draw to the 3D view via the protobuf implementation of GLOverlay messages.

Introduced persistence in RGBDview, needs debugging, fixed a bug in param reading in the simulator, pushed message sender a bit forward, not working yet

Also updated all the units for the heartbeat values that are exposed to the realtime plotter to follow the suggestions laid out by the documentation for valueChanged().

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().

Exposed HEARTBEAT.system_status and HEARTBEAT.base_mode to the realtime plotter widget via the valueChanged signal.

Changed the drop rate from a SYS_STATUS message to follow the MAVLink specs along with some extra range checking.

Added a workaround to the mission management code where it would only accept messages addressed to the MAV_ID_MISSIONPLANNER component. This was causing problems with the send-loss value being calculated, so I decided to add this until a proper solution can be developed.

Refactored part of MAVLinkProtocol::receiveBytes() as I was trying to debug within it. Nothing major, though I did remove an unnecessary loop.

Added multi-UAS support to QGCRGBDView. Fixed display timeout issue on computer for which data source is not time-synchronized.

Code changes to reflect new header information (sysid, compid, timestamp) in protobuf messages. Added protobuf message timeout; old messages will not be visualized. Fixed getParameterValue in ParamManager; the method can segfault if the component id or parameter id is not valid.

Added support for reading uint8 values from an autopilot via QGC. Still need to add support for writing them.

Some more bugfixes and improvements for the Mission Plan widget. The "current"-checkbox in "Onboard"-waypoints can no longer be changed by clicking directly, but it is handled internally by QGC. Now there should be one and only one checked checkbox, which shows the last KNOWN "current" waypoint on MAV. The white border around an unchecked checkbox means, that the user is requesting the change of current waypoint, but QGC has not received MISSION_CURRENT message as a confirmation yet. Also,if there is no response from UAV after pushing "Read" or "Refresh", the "Onboard" list will be deleted to indicate, that there is no information available.

Added visualization of obstacles. Fixed relative font path issue in 3D widgets by using QFont within osgText::Font instead of using static font filename.