Adjust stylesheets to render menubar items correctly.
There is a *bug in Qt5 (as of 5.3.1) where QMenuBar::items don't inherit their background colors, but revert to default system styling. The work around is to explicitly color their backgrounds.
Add action item to MainWindow.cc
Remove old dead code from MainWindow.cc
Fixed missing argument in debug messages. Now they're readable!
Merge pull request #778 from Susurrus/master

Fix remaining Windows issues on Qt5
Merge remote-tracking branch 'mavlink/master'