IWD check in download

[Mitch]

I added a iwd / ff check to cod4 now too. I had some trouble with the query limiter version. (some differences with functions addresses)

Invalid download attempt: main/server.cfg
clientDownload: 0 : beginning "fail.iwd"
clientDownload: 0 : "fail.iwd" file not found on server

https://github.com/M-itch/libcod/com...e81b96dbf6e2a5

Edit: i still should do some testing to check if it works correctly