Remove zml-repo from pom.xml as it failed to resolve anymore

Remove zml-repo from pom.xml as it failed to resolve anymore, causing Maven builds to have to wait for extended periods of time

The repository at http://files.zachsthings.com/repo fails to resolve anymore, and is causing Maven builds for WorldGuard and anything with WG as an upstream to hang while it attempts to download org.bukkit:bukkit:1.6.2-R0.1-SNAPSHOT

Tested ability to build by clearing out local dependencies and rebuilding, as described here: http://stackoverflow.com/a/2776387/979574