Fixing the prism damage bug in official map pack maps.

[Blade]

I've done a bit of research and contrary to what the UMP documentation says from Marshall, I believe this to be fixable within a mod. The YRO files are normal mix files and they get loaded first out of any mix file. That means that any file within them is superseded by an identical file name in a mix loaded later in the order (both expand and ecache files fit this description). Thus a mod can replace these maps with new versions that the official versions cannot overwrite, but that won't be playable until the YRO files are installed because the .pkt file needed for each map is loaded from them.