Updates pom.xml

Adds my nexus repository to the pom.xml. Alters factions and mcore versions to snapshot ones.
This is all, so that DragonTravel can be built on my Jenkins so people can try development builds and have earlier access to new version since the Bukkit staff have some time to check new versions before they are published.

The reason why we are using my nexus and other versions of mcore/factions is because there is no maven repository holding those two artifact unfortunately, so I had to setup my own stuff.

This also enables DragonTravel to be built on your own system without doing any fancy repository "hacks", since every dependency is available somewhere.

After you have merged this pull request you must add my http://ci.xemsdoom.com site to the service hooks.

Check out the CI sites: http://ci.xemsdoom.com/view/Bukkit%20platform/job/DragonTravel/
And of course the status badge: [![Build Status](http://ci.xemsdoom.com/buildStatus/icon?job=DragonTravel)](http://ci.xemsdoom.com/view/Bukkit%20platform/job/DragonTravel/)