update the cbits code to current lz4

...release of march 2nd.

Passes the quickcheck suite


At some point in the near future I might be exploring modifying lz4 c code itself if theres a sane way to lift the 4gb file size cap on 64 bit architectures, but thats a whole 'nother adventure.

Note: per se no reason (for now) to update the c code, but no harm i think since it passes the test suite