qobject_cast is times faster dynamic_cast for objects that
inherit QObject. also, use auto keyword to not duplicate
class names.

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

The earlier sleep calls disabled the app event queue, leading to "beachballing" in Mac OS and a visible boot delay / jitter. Running the event loop actively while waiting prevents the UI from freezing.

Prevent shutdown ordering crashes

This mechanism automatically queues data into the correct thread where necessary, otherwise the method is invoked directly with low overhead.

At the same time remove the UDP socket event workaround. It is not a problem.

Plus other auto connect bug fixes

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>

Windows OS doesn’t disconnect port when you pull plug on USB. This
caused all sorts of problems with previous logic. New logic handles
this correctly.

- 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

- 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

Instead us a Toolbox concept which hangs off of QGCApplication

This is needed for Android since it needs to communicate with java apis
which require everything on the main thread. The additional thread was
not really needed since you can implement using a signal based approach
which ends up being the same thing.

Still not working right...

Link ids were being used interchangeably with the mavlink channel for
the link. Link ids handed out as a numerically increasing integer. Once
the counter went past MAVLINK_COMM_NUM_BUFFERS all hell would break
loose and cause memory corruption.