Implement HPACK 07

* http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-07

Implemented features
* Huffman encoding
* Static table indexing
* Reference set
* Increment/noindex/neverindexed
Merge pull request #3 from lepidum/hpack-07

HPACK 07
Implement Framer, Stream, Connection, Client, Server for h2-12
Merge branch 'stream-h2-12' into hpack-test-case

Conflicts:
	lib/http/2/compressor.rb: use stream-h2-12.