Implementation of Battery Monitor configuration, and addition of AP2ConfigWidget, which automatically handles UAS connections to allow for simpler configuration window code.

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.

Removed OpenGL dependency in HUD, merged in HUD from Soren Kuula and config changes from Michael Carpenter

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.

Whoops. Look like you can't inherit from QToolBar using Qt Designer. Restored last set of code. Also, changed one of the QToolButtons to a QLabel in QGCToolbar.

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.

Switched button coloring so they're default grey with a :hover of blue instead of the other way around.