th175: normalize filenames in fileslist
th175: normalize filenames in fileslist

The th135 games use backslashs, th175 use forward slashes, the
th135 hash function in thcrap support both slashes, the filenames
dump made by thcrap uses backslashes, the fileslist.js I have from
the 1st demo uses forward slashes... Let's just support both here
as well.

thpatch/thcrap,thpatch/thcrap,thpatch/thcrap,thpatch/thcrap,thpatch/thcrap