Added right-click option to select MAV, ensured that waypoints get updated properly on switching MAV

Fully working waypoint interface, thoroughly tested. Active waypoint setting has to be debugged in the simulator, but works fine on real hardware

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

Working on better simulation implementation, fixed a bug where the port handle was not fully released

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

First semi-usable version with new menu layout based on autopilot. Still very experimental. Current Bug: Linecharts do not work. Need to find out why