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.

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

There are many ways of iterating over lists in C++/Qt.
In the specific case of QStrings, it is known [1] that using
foreach with const references avoids the creation of new
QString objects in each iteration, reducing the time consumed
by the loops.

[1] https://blog.qt.io/blog/2009/01/23/iterating-efficiently/Signed-off-by: Anselmo L. S. Melo <anselmo.melo@intel.com>

- 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

Fix the corner case of a system running on localhost using the network and the loopback address in parallel. Force it onto the loopback interface.

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.

Also fixed a typo (copy/paste error) in the TCP link settings loading where it was using the UDP port as the default value instead of the TCP port.

This came through google groups and as the change is right where I'd been working, I added it here to avoid collision.

The goal of this first installment is to organize the code a bit so it's more readable,
clean up a bit of left over cruft, and manage link configurations (and links in general).