* Fix#76 fastcdc chunk boundary off-by-one.
This ensures that the last byte included in the gear-hash that identified the
chunk boundary is included in the chunk. This ensures chunks are still matched
when the byte immediately after them is changed.
* Init gear hash to all 1's to prevent zero-length chunks with min_size=0.
Also change the `MaxChunkSize` test to use min_size=0 to test this works.
