Revert "crc32: major optimization"

This reverts commit ba326fa09fdf1b6ba708b924258cec91ee1400f6.
Revert "crc32: some minor cleanups"

This reverts commit d4f68f00f749264f2362a5b7c18ab56ed2c7d172.
Revert "crc32: minor optimizations and cleanup"

This reverts commit 3022aca0cdeb7c8adf6057bb53754c58e0aad835.
Revert "Revert "Completely updated crc32 lib""

This reverts commit 1f7c37069c31503edbd407d3a40934b17677b455.