Add crc32 and adler32

[karolzlot]

adler32 is faster than other included hashes and often it is good enough. crc32 is similar but not that fast.

[karolzlot]

I tried to use this workaround but it doesn't work with dirhash-python (it works well on its own however, I can hash files manually):

https://stackoverflow.com/a/5061842/8896457

It results in exception: ValueError("unsupported hash type crc32")