Updated MAVLink to handle video stream types (auto discovery)

Fix support for single vehicle coming and going

ArduPilot option to not start mavlink streams

Allow window to size to down to as small as you want

Expose guided altitude settings. Rearrange Fly and Plan view settings.

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Fix Plan save message on exit

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Enable/Disable based on fixed base position

Add support for specifying fixed RTK base position

Added support for qgcRebootRequired Fact meta data value.

Prevent clicks going through top level items

Fixed the core MAVLink receiver. Among other things, it wasn't accounting for fragmented messages.
Fixed code that monitors messages received (and lost)
Added a section within the MAVLink panel to show the current status (for the current vehicle)
Remove some old, unused exposed interfaces

Add new Help page under Settings

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Add test for an existing window before attempting to close it.

Show the link indicator in the tool bar if two or more links are connected and at least one of them is a high latency link.
Show in the link indicator if a link is inactive.

- Improve function names
- For notifications of an active link change only show the priority keyword if multiple links are connected
- Use QMap instead of QList for the HeartbeatTimers
- Style improvements
- Simplify sending the MAV_CMD_CONTROL_HIGH_LATENCY command

This setting enables/disables the LinkIndicator toolbar in which the primary link can be chosen.

The LinkIndicator shows the connected links and lets the user select the priority link,

Automated preflight checklist: Initial commit. Note that this requires an autopilot firmware that writes the respective health flags in the SYS_STATUS mavlink message