Merged eb/gcell-wip -r10213:10230 into the trunk. This reduces the
overhead of off-loading jobs, such that it is now feasible to off-load
50us jobs on the QS21 and 10us jobs on the PS3. See wiki:Gcell for
performance graphs. There is still plenty of room for improvement.
I'll be revisiting this in a week or so.
git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@10231 221aa14e-8319-0410-a670-987f0aec2ac5