v3.0.0

unicorn 3.0.0 - disable rewindable input!

Rewindable "rack.input" may be disabled via the
"rewindable_input false" directive in the configuration file.
This will violate Rack::Lint for Rack 1.x applications, but can
reduce I/O for applications that do not need a rewindable
input.

This release updates us to the Kgio 2.x series which should play
more nicely with other libraries and applications.  There are
also internal cleanups and improvements for future versions of
Rainbows!

The Unicorn 3.x series supercedes the 2.x series
while the 1.x series will remain supported indefinitely.