Add Bukkit repository to fix builds

    [ERROR] Failed to execute goal on project zPermissions: Could not resolve dependencies for project org.tyrannyofheaven.bukkit:zPermissions:jar:1.1-SNAPSHOT: Could not find artifact org.bukkit:bukkit:jar:1.6.2-R1.1-SNAPSHOT in tyrannyofheaven.org (http://maven.tyrannyofheaven.org) -> [Help 1]

This PR fixes it.