Import Skein code from NIST CD submission
Make checksum algorithms pluggable
Fix handling of huge buffers (>2GB) in LZP
Cleanup of some buffer sizing code
Speed up CRC64 calculation in dedupe chunking
Add generic pre-processing wrappers for future support of other pre-processors.
Clean up computation of Rabin block sizes.
Compute Rabin scratch space accurately to avoid RAM wastage.