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

Cleaned up serial port libs, activated mav visualization on map (still debugging), fixed standalone MAVLink generator

Added version check for settings to prevent application crashes because of old, incompatible settings

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

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