Merge pull request #62 from jnicklas/single-build

Make sure watcher doesn't trigger multiple simultaneous builds
Merge pull request #59 from jnicklas/connect-redux

Rewrite server as a connect middleware
Update CHANGELOG
Release version 0.2.5
Release version 0.2.6
Bind to `localhost` instead of `0.0.0.0` (whole wide world) by default
Release version 0.3.0
Add option to proxy requests to another server