LZ4 : New version

Yesterday's experiments provided some appreciable gains to LZ4, and therefore it seems valid to share them.

The new version of LZ4HC is, on average, 10% faster.

On top of that, i found an optimization in the decoder, which is valid for any LZ4 version.
As a consequence, both the "Fast" and "High Compression" versions get updated with a nice boost to decompression speed. LZ4 already was the fastest decoder, this makes it even better.

You can download both version at their new LZ4 homepage.

	Compression Ratio	Speed	Decoding
LZ4 "Ultra Fast"	2.062	227 MB/s	780 MB/s
LZ4HC "High Compression"	2.345	31.0 MB/s	830 MB/s