The dark css is the master and contains all style information. The
light css is the slave and only contains color information.

Also added a corresponding style for the light themes to make it a little prettier (though it wasn't broken on light themes).

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.

Fixed race issues in config upload, tested to be reliable now - board startup scripts now need the other half of testing

Fixed styling of the toolbar, specifically coloring and sizing of the buttons, and made the labels aware of the current window theme. Also made some changes to updating the toolbar when switching UASes or when UASes disconnect/reconnect.

The QGCUnconnectedInfoWidget now remains square and has more rounded edges so that it looks more like a button.

The light and dark themes now use slightly different blues for their accent colors that is higher contrast.

The background color of the mission items is now controlled by stylesheets as well. This change also fixed restyling the mission lists when a style change occurred.

Reworked the UAS listing. It's organized differently and styled differently. Also the fading of the heartbeat status now works properly. Also fixed some theming issues with the connectButton when it was checked.

Synchronized the dark theme to the changes to the light theme from the last commit. Also made more text change color based on selected theme.

Extended most of the new toolbar theming to the dark theme. It looks pretty good, though both themes still need some more refinement.

The toolbar now displays much nicer under the light theme. Also colorized the connect/disconnect & delete buttons in the communications settings window.

Reduced the QDockWidget's border down to 1px wide. Annoying to have 10px border on the widgets when they were floating.

Removed the UnconnectedUASInfoWidget class as it could be replaced with a simple QLabel with the same functionality. Also styled the NO UAS warning on the ReadOnly mission view so it looks good in both dark and light themes.