This removes double emit of signals.

This api doesn’t make any sense given the fact that LinkInterface
signals bytesReceived with the bytes in the signal. Also the reason why
it is never called!

QSerialPort buffering too slow on Windows.

Settings versioning is handled at the uppermost level with a version
stamp.

This test is too flaky to run in TeamCity reliably.

Conflicts:
	src/uas/QGCMAVLinkUASFactory.cc
	src/uas/QGCMAVLinkUASFactory.h