Starting the shitz
Introducing the concept of nodes and solving conflict

As we discussed, I created the case class 'Node' and changed the treeDecomposer according to it.
There are a few todo's that need to be taken into account. I'm going to try to do the skeleton for compression

Conflicts:
	plugin/src/main/scala/scala/reflect/persistence/Plugin.scala
Changing Node structure

I replace the pos attribute by an Option[Position] seems less dirty than initializing it with a null