Add new ArduPilot VID/PID

Work around message disassembly issue on ARM 32-bit.
Fix memory leaks.

Allow plugin to add flight modes to joystick button actions

Move analyze page list model to the core plugin.

Tweak chart colors

UI tweaks

Limit chart to 6 series (arbitrary)
UI tweaks

WIP - MAVLink chart as a control. Add any number of charts with any number of series. All individually controlled.

Add custom chart header

Heading value should be real so NaN comes through

Only trust gcs heading from plugin

Fix MAV_CMD_IMAGE_START_CAPTURE unit test usage for take photo

Fix MAV_CMD_IMAGE_START_CAPTURE usage