Correct order of rotations to get roll, pitch and yaw corresponding to classical aeronautics convention and coherent with Fly view

Subclass of QMessageBox which re-implements the static public
functions. There are two reasons for this:
1) The QMessageBox implementation on OSX does now show the title
string. This leads to message boxes which don't make much sense. So on
OSX we set title to text and text to informative text.
2) If parent is NULL, we set parent to MainWindow::instance. This
prevents message boxes which can go behind MainWindow

Using QFileDialog directly on OS X can hang intermittently due to Qt
bug.

This is the Pixhawk research board, not the PX4 production board.

also adds AMSL output in ft

Use a pragma around our use of that header to silence the warning. OSG
3.01 has these warnings, 3.2 has fixed them, but 3.2 doesn’t isn’t the
widely used release yet. So at some point when we upgrade to 3.2 this
will no longer be needed.

Use a pragma around our use of that header to silence the warning. OSG
3.01 has these warnings, 3.2 has fixed them, but 3.2 doesn’t isn’t the
widely used release yet. So at some point when we upgrade to 3.2 this
will no longer be needed.

Altitude splitted to altitudeAMSL and altitudeRelative, speed splitted to airSpeed and groundSpeed. PrimaryFlightDisplay uses airSpeed for FW and groundSpeed for MC.

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.

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.

Addressed issue #26. Select System, Plugins and System are disabled when neccessary. Removed style-outdoor-dark.css. Moved the other two .css files and Vera.ttf into files/styles.