Automated preflight checklist: Initial commit. Note that this requires an autopilot firmware that writes the respective health flags in the SYS_STATUS mavlink message

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Try/Finally causes window to close all the time

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Create a "Dead Mouse Area" control to eat mouse events underneath desired area. This is to prevent mouse events from leaking through controls underneath the area.
Replace original "NoMouseThroughRectangle" as this is more versatile.
Prevent mouse through events from leaking underneath the Fly View tool strip.

Seems to work fine without out.

Moved "Grid Lines" out of General Options and into the Video Stream Widget
Made a QGC custom Switch element

Also hand carried text to speech changes from Stable to master. Plus
unit tests for that.

For whatever reason, showing the dialog through a function causes a crash in QML (undebugable--new word!)