PR Custom example theme

Added Light theme

This is a small experiment into creating a custom theme for QGC.

Tweaks

When dealing with an automatically configurable video stream, handle the video source automatically as well.

Add external zoom buttons

Fix case

Quick access to thermal modes

Custom gimbal control

Custom tweaks

Keep track of gimbal position locally.

Show heading on waypoint if multi-rotor.

Joystick Work

Old instrument panel layout as alternative

Update APMRover metadata

CentOS Build Instructions

We don't have to restart video when stream config changes

Microhard improvements