The derived class wasn’t really adding any capabilties

Fixes bugs with savings settings for the window state, theme, UAS-connected view, and low-power mode.
Also removes some unneccesary logic that attempted to handled unclean shutdowns, which I haven't
been able to reproduce.

It was a poor proxy for better coding around the problem of bad settings or the lack of
settings on first-run.

No functionality changes in this code, just code clarify improvements.

Splash screen is optional. Also remove some unused class definition.

- allow unit tests to use QGCApplication
- clear global singletons for each unit test run

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

- Logging now always on to temp file
- User prompted to save temp file after disconnect
- Orphaned temp logs checked for on boot
- Logs saved to new save file location
- Log file starts/stops with first and last connnection

Also fixed bug in loadStyle

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

Conflicts:
	src/uas/QGCMAVLinkUASFactory.cc
	src/uas/QGCMAVLinkUASFactory.h

No major functionality changes.

Both on the backend (replaced with DEFAULT view) and on the front end (removing UI menu items).

Includes removing an if-statement that should've been dead but was erronously applied to the following statement. Dead code = bad, if-statements without braces = bad.

This was deprecated on Febuary 3rd, 2014 and removed a little later. This finally completes that process.

SLUGS has maintained their patches out-of-tree for a long while now.
These will eventually get merged back in, but it'll be easier to evaluate them as fresh commits instead of modifications to this old & dead code, so we'll delete this for now.

Fix HIL link reconnect issues due to missing threading flag usage, warn user about missing config and take him to config view if necessary

Fix HIL link reconnect issues due to missing threading flag usage, warn user about missing config and take him to config view if necessary

MainWindow::loadDataView has been commented out for 9 months now.
Removed commented out code instead of leaving cruft in.

Added documentation and clarified messages to the user.

This feature can be enabled at compile-time and documentation has been added to the README.