unicorn 0.10.3r

Removes the Rev monkey patch, rev 0.3.0 is out now so we can
just depend on that instead of monkey patching it.  Experimental
HTTP keepalive/pipelining support has arrived as well.

Three features from mainline Unicorn are now working again with
this branch:

* Deadlocked workers can be detected by the master and nuked
* multiple (TCP) listeners per process
* graceful shutdown

This (pre-)release does NOT feature HTTP/0.9 support that
Unicorn 0.91.0 had, expect that when this branch is ready for
merging with mainline.