Fix ui sequencing when bootloader not found

LinkInterface and Vehicle uses mutexes to synchronize writing bytes to the link instead of queued signals

Cherry pick joystick fixes from stable and fixup merge

App messages now use simple modal message dialogs. Vehicle messages continue to use non-modal popup.

Add support for multi-press joystick buttons

 - UVify Core board support is implemented.

More changes to ArduPilot manifest lookup

Even better manifest logging

Better logging for ArduPIlot manifest lookup

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

Fix showPanel calls

Prevent view switching apis support a stack

Add view switch prevention

Fix textRole usage for QGCComboBox

Enable ArduPilot motor testing

Fix mad merge

Adjust merge to Stable code

Support up to 64 buttons, not limit to 16
Send a single button command and not a stream of commands at 25Hz
Send button commands through signals (it's coming from a different thread)
Hide gimbal support through analog channels (there are no MAVLink messages to handle it)

FMUK66 updates

Map gimbal controls
Keep track of gimbal position within Vehicle

Add gimbal to external control signal