More multiplayer progress #3

This may be the second-to-last update before I take it out of the multiplayer_test beta branch. Afterwards I'll start working on more abilities and weapons. Also more enemies will be added afterwards. [h1]Changes[/h1] [list] [*] New internal ability/weapon code to make it easier to create new ones! [*] The red explosive enemies now do damage to anything nearby instead of just who touched them [*] Enemies spawn in random locations around the arena instead of in a clockwise loop [*] Free Trinity boss spawns outside of the arena [/list]