small_iters problem: in-place and buffered codecs that overwrite their input (all but checksums) encode the given data only during the 1st small_iter. Possible solutions:
* drop si; instead of N si have N copies of data stored in RAM
* forbid si>1 for codecs where it doesn't work
* add memcpy where it's needed (very bad for checksums because they are too fast) 

make lzwc work with multiple blocks
add the AES implementation used by vmac/umac; add vmac/umac
add mmini-lzh
add http://code.google.com/p/variablelengthstringhashing/ 
* with a fast PRNG (xorshift?)
* with a fast crypto PRNG
* with a static precomputed random sequence
add hashes from http://www.fastcrypto.org/
add:
* https://github.com/zfy0701/Parallel-LZ77
* htps://github.com/matuba/LZSS
* https://github.com/Wuestenschiff/myLz77
* https://github.com/m3h/lz77
* https://github.com/Cereal84/LZ77/tree/master/source
* https://github.com/ky1000ky2000/lz77/tree/master/lz77
* https://github.com/stevesan/lz77
* https://github.com/Sanguinarious/lzh-improved
* Sanmayce's hashes - there's SSE version that doesn't compile with GCC and could be ported
* reintroduce LZ4bz

Allow more than 1 option passed to a codec, i.e. tor:10:ht4