lzs-decompress: copy code for lzs_decompress() method from lzs-compress
lzs-decompress: copy code for lzs_decompress() method from lzs-compress

No point in re-inventing the wheel. The lzs-compress code had more
consistent style, and used fstat() to get file size for malloc.

cmcqueen/lzs-compression,cmcqueen/lzs-compression,cmcqueen/lzs-compression