Added angle conversion testing, added battery settings option, added option to set MAVLink ID of groundstation

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

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