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.

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/)