This reverts commit ac73682a.

Fixed all the bugs the new tests found

This makes VehicleComponents reusable from core plugin without
requiring override of prerequisiteSetup

Prevent shutdown ordering crashes

* enable TCPLinkTest
* enable FileManagerTest

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.