unicorn 4.4.0 - minor updates

Non-regular files are no longer reopened on SIGUSR1.  This
allows users to specify FIFOs as log destinations.

TCP_NOPUSH/TCP_CORK is no longer set/unset by default.  Use
:tcp_nopush explicitly with the "listen" directive if you wish
to enable TCP_NOPUSH/TCP_CORK.

Listen sockets are now bound _after_ loading the application for
preload_app(true) users.  This prevents load balancers from
sending traffic to an application server while the application
is still loading.

There are also minor test suite cleanups.