The recomposer fully implemented, to be tested.

The recomposer is now totally programmed. Still have to test it.
Creation of a new Node type : separator, used to reconstitute
the list of childrens afterward, while recomposin the good ASTs.
Merge branch 'master' of https://github.com/aghosn/persistence

Conflicts:
	plugin/src/main/scala/scala/reflect/persistence/AstNode.scala