Convert to maven project

-Convert to maven.
-Reorg work directory to be inline with Bukkit best practices.
-Added PlayerChecker.java from https://github.com/Steffion/MVote
-Added players.yml to prevent error on server startup when no players
had been saved yet
-Compiled against Bukkit 1.6.2-R0.1
-Tested on Bukkit 1.6.2-R0.1 with Votifier 1.9