Added list of valid key signature values to docs.
Bugfix: Python 3.4.0 prints version to stdout breaking ./run_tests.py.
Improved check_str() a bit.
Tiny reformatting in portmidi.py.
Bugfix: PortMIDI input busy waited in receive(). (Reported by Francesco Ceruti)
Updated changelog.
Added a comment.
Moved "a callback is set" check from backends to the base class.
PortMIDI backend: moved _send() into _receive() and simplified implementation.
Rewrote a comment.
Rewrote PortMIDI thread_main(). (It also used 100% CPU.)
Updated setup.py.
bugfix: package didn't work with easy_install.

(Issue #14, Reported by netchose.)
Bumped version.
Added Sphinx PLACEHOLDER to manifest to keep check-manifest happy.
Added wheel support.
Updated changelog.