(1) server/autotest.py can run a client test in background.
This feature is dangerous (because it leaves the client test running on the DUT outside autoserv's control) and only used by one test (power_USBUnplugInSuspend) that hasn't run in a while.

(2) A client test also has the notion of "steps", which allows the test to be continued past a reboot. There is server side support to --continue such a test. This feature is unused. The preferred way to get this functionality is to write a server-side test.

Both these features are untested, possibly broken, (somewhat) dangerous and are making improving parsing of the results hard (because of arbitrary result nesting from the client side).

So, I'm dropping them. In the process, I'm breaking the one test that uses the background feature. Both these features have already been discussed on the relevant mailing lists, so it shouldn't surprise anybody when they disapear.