New rules for submitting maps.

Damn, just one more vote is needed for the idea of creating sections to tie with the leader.
I'm still in favor of creating sections first (multiplayer/single-player), but if it's decided to rename them, then the multiplayer/single-player parameters should remain the primary ones, so they should be placed at the beginning of the topic title, followed by the size letter, then the map name, and finally the author if necessary.