Fixes SRB2MB: [Linux]Filename is truncated on download screen. Turns out the full path name (with DOWNLOAD/ or [home]/DOWNLOAD/) was being truncated, THEN what's left of the actual file name in the truncated name was used of that. That's just silly, all we need to care about is the actual file name itself.
I also improved the behaviour for extremely long filenames (even without the path) - ellipsis is now used in the middle to shorten the name, as seen below:
(the full name was abcdefghijklmnopqrstuvwxyz1234567890.wad, just so you know :) )
