#1 crc checking is of dubious quality

[Willem Kossen]

Yep, it is. for now the script checks whether the
md5sum of the downloaded files occurs in the idx files
at all. if it does we assume it's ok (that's probably good
enough.) of couse this is not very nice. I have to make
some code to extract the crc's for each file and verify on
a per file basis. this however takes time.