Header compression implementation

Node-http2 now implements the first Header Compression draft. The
compression code is pretty self-contained, and can be used in itself as
well. A blog post with usage examples is published on my blog[1]. The
source code, unit tests, and documentation is available on GitHub[2][3].

The code is probably not without bugs, and not all corner cases are handled
well. If you find any issue, please report it in the issue tracker or email
me directly. Any other feedback is also welcome.

[1]:
http://gabor.molnar.es/blog/2013/07/03/the-http-slash-2-header-compression-implementation-of-node-http2/
[2]: https://github.com/molnarg/node-http2
[3]: http://molnarg.github.io/node-http2/compressor.html

Regards,
  Gábor