Services

This is an attempt to make custom AsyncMultiService usable inside an advanced master.cfg or a buildbot plugin.

You can start review by looking at the doc in the end of the patch. I hope this explains the idea.

Yes, our android process includes 6 singletons we have issues to reconfigure according to the master life cycle. (mostly txrequests based rest services clients)
The reconfigurableServiceMixin was something that looked a good solution to clean that up, hence this upstream first contribution. The next problem will be to back port that on our buildbot eight frankenstein..