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.

Significantly improved plotting, now capturing data in linechart allows limmediate processing / analysis of the whole flight

Improved runtime performance, currently hunting down a bug where the whole application gets repainted although only parts of it are refreshed