Minor cleanup, fixed a bug where the serial port would not connect on first application launch on Linux

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

Set the remote address of the xbee via the xbeeconfiguration window and save last address in a txt file. Xbeelink ist still hardcoded to work with series2 xbees

port has to be closed and deleted in the same thread as it was created. changed the disconnect function