Removing UASes now returns the UI to an almost pristine state. This was done by altering the activeUASSet signal so that it can emit a NULL UAS. Crashes may still exist in autopilot-specific code.

Partway through refactoring of UAS deletion. This is in order to actually support removing UASes from QGC, which is currently impossible.

Update README

Removed OpenGL dependency in HUD, merged in HUD from Soren Kuula and config changes from Michael Carpenter

This reverts commit 233a1716.

Impl. Lorenz suggestions wrt one velocityChanged, altitudeChanged, speedChanged signal per reference frame. Impl. CDI on compass disk.

Change so MainWindow handles its own deletion, and deletion of other UI objects to allow for closing when the MainWindow is closed, regardless of if other windows are open.

Change for the new RC calibration widget, still needs an if/else to load the old one for unsupported systems

Changed OS X build instructions to force qmake to generate a Makefile instead of xcodeproj files.

Refactored QGC startup so that MainWindow::instance() is usable everywhere. This was required to get the styling working properly for ChartPlot.