This extension introduces a complete version handshake mechanism which will detect wether the vehicle AND the complete link / routing infrastructure support MAVLink 2. If they do, QGC will switch to the highest protocol version supported by all connected vehicles. If a new vehicle connects, it will re-negotiate the highest possible version. This means that we error on the side of compatibility, which later can be easily changed.

Instead of hardcoded "QGroundContorl" strings

* Holds all the settings for the app
* Allows core plugin to override default values

Use component id from heartbeat

Prevent shutdown ordering crashes

Made QGCCorePlugin derive from QGCToolBox and expose everything through the same mechanism as everything else.

_finalize methods need information which is not available if all you
have is a mavlink_message_t

Includes ability to load params

Temporarily disable MAVLink version check as the QGC settings have no effect and it will mess with the upgrade from v1 to v2 and has no real value

Plus other auto connect bug fixes

I removed some needed headers from a top level file which then causes a
ripple effect downstream

- Also fix vehicle selector dropdown in toolbar

- Pervasive change to automatically connect to known board types
- Lots of additional changes along with this:
- More exposure of objects/properties to Qml
- Much restructuring in LinkManager and LinkManager clients

- Pervasive change to automatically connect to known board types
- Lots of additional changes along with this:
- More exposure of objects/properties to Qml
- Much restructuring in LinkManager and LinkManager clients