v4.4.3

Rainbows! 4.4.3 - bugfixes for EventMachine users

This release fixes two EventMachine bugfixes from Lin Jen-Shin
and Mark J. Titorenko.  There are also some minor cleanups.

Lin Jen-Shin (1):
      event_machine: avoid close on deferred response

Mark J. Titorenko (1):
      event_machine: join reactor_thread if it is already running

Eric Wong (2):
      event_machine: cleanup confusing assignment
      t/GNUmakefile: cleanup test dependencies