Merge pull request #14 from jasnell/master

Delta + BOHE
Similar to http1_gzip but restricted to Z_HUFFMAN_ONLY strategy
Merge pull request #15 from frkay/master

http1_huffman zero cost compressor (zlib using Z_HUFFMAN_ONLY strategy, immune to CRIME)
take an argument to determine encoding; choices are "ascii" (default), "seven" (seven-bit) and "huffman" (zlib huffman encode).
Added the 'delta2' compressor, which is very similar to the 'delta'
compressor, except that it should be easier to understand.
With another modification, it should also be as efficient on the wire.
Instead of using a tree of keys containing trees of values and a
linked-list of LRU entries, it uses a straight-up LRU of key-value entries.

Also, the various codecs were modified to include the .name field as now
required.
Found and fixed a really really stupid performance sapping bug.
Basically, the function which formats bit-arrays for human consumption
was being called for every character of every string encoded in the
huffman encoder. It wasn't even displayed, so this was worse than useless.
Also fixed a formatting bug.
Basic bohe encoder (without delta, based on the current I-D)... and
updated delta2_bohe derived from the newer delta2 compressor.. still no
decompression, that's coming soon, I promise