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

Cleaned up serial link handling, eliminated double menu entries and safeguarded the link list. Did intentionally not improve the object dependency issue, will work on that on a global scope

Added not yet working version of logging / log replay, fixed ALL bugs in main window, enabled full persistence in main window and serial link.

Improved line chart, brought back movement on HUD (but still looks somewhat wrong on the dials). Fixed logging for ground time mode

Fixed SLUGS related warnings. Commented the visibilityChanged connection (MainWindow.cc 535) because it does not take into account when the widget is hidden when changing perspective. Will work on a fix

Fixed multi-thread message window bug, mainwindow should not hang any more on message windows from comm threads

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