Instead us a Toolbox concept which hangs off of QGCApplication

Changing the order of the QGCFileDialog::getSaveFileName() function. The idea was to expand the existing QFileDialog version but as we removed the selectedFilter, we might as well make this more intuitive. The options argument is the one trully optional and should be last.
Adding an example to the documentation on how to go about figuring out what file type was returned by these functions.

Removed the “selectedFilter” argument from the QGCFileDialog functions along with references to it in unit tests.
Fixed function declarations and prototypes formatting while at it.
Changed the caption of a few file save dialogs with a more descriptive text (explicitly telling what is being saved).

QGCApplication::saveTempFlightDataLogOnMainThread()
MainWindow::startVideoCapture()
QGCBaseParamWidget::saveParametersToFile()
QGCDataPlot2D::savePlot()
QGCDataPlot2D::saveCsvLog()
WaypointList::saveWaypoints()
QGCToolWidget::exportWidget()
LinechartWidget::startLogging()

Making sure defaultSuffix doesn’t start with a dot (i.e. “.bar”)

QGCFileDialog::getSaveFileName()

Assert if defaultSuffix contains a dot (i.e. “.bar”)

UnitTest::_getSaveFileName()

Revert premature assumption that adding support for selected filters in Open Save would not affect all other file dialog operations. As is, unit tests requires all or nothing.

WIP issue #1173. Adding default suffix (extension). While at it, added selected filter support and removed unit test assert about its use.

Plus a large number of other changes to allow for orderly shutdown of
objects without crashes or asserts. This is need for unit tests to
create/delete global state around every test.

Allows for UI unit tests to be written:
- Ability to respond to expected message boxes
- Ability to fail test if unexpected message boxes occurs