Reject parsing alphanumeric hashes

Now specifically checking for certain hashes during validation phase before parsing.
This will actively refuse to parse anything that starts with at least 32 alphanumeric characters.

Also reverted the previous modifications to the regex since those were no longer needed.

Btw. the 'success' counter in the tests is to determine the percentage. Without the modifications about 1/10 of random hashes got parsed to something.