unicorn 1.1.4 - small bug fix and doc updates

We no longer unlinking actively listening sockets upon startup
(but continue to unlink dead ones).  This bug could trigger
downtime and nginx failures if a user makes an error and
attempts to start Unicorn while it is already running.

Thanks to Jordan Ritter for the detailed bug report leading to
this fix.

ref: http://mid.gmane.org/8D95A44B-A098-43BE-B532-7D74BD957F31@darkridge.com

There are also minor documentation and test updates pulled in
from master.  This is hopefully the last bugfix release of the
1.1.x series.