Mavlink terrain protocol support

Drive Plan view ROI support from firmware capability bits

Allow plugin to add flight modes to joystick button actions

Plugin'ized follow me support

Instead of trying to keep a vehicle type within the FirmwarePlugin instance, pass the vehicle to the function so it can query the type that way.

Clean up parameter meta data version methods to match spec

Smart RTL support

Remove the concept of reserved buttons for manual control

Add gotoFlightMode method

FirmwarePlugin: Issue a warning upon connecting if the firmware in use is not using a stable release

Buggy and no longer needed

Needed to support different indicators for advanced mode

Remove/comment off debug output pollution

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