Clears the persisted settings for the QGC

This reverts commit e003dd7a.

Change of name for diydrones fork of QGroundControl to APM Planner 2.0, per Chris Anderson and Craig Elder

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.

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

Fixed some destructor commands

Added a qDebug() message handler for windows installs that have no debug helpers. Hunting bug in Mode change in UASView

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