Make /ma playerlist pattern less greedy.

This commit changes the pattern of the player list command to one that
isn't quite as greedy. This change is enough to fix issue #676 and thus
allow MobArenaStats to take control of its own command.

The command framework could definitely do with a bit of a rework away
from pattern matching towards aliases, which would prevent similar
issues from cropping up down the line. For now, this is good enough.

Fixes #676

src/main/java/com/garbagemule/MobArena/commands/user/PlayerListCommand.java

@@ -14,7 +14,7 @@ import java.util.List;
 
 @CommandInfo(
     name    = "playerlist",
-    pattern = "player.*|listp.*",
+    pattern = "players|playerlist|player-list",
     usage   = "/ma players (<arena>)",
     desc    = "lists players in an arena",
     permission = "mobarena.use.playerlist"