Tree Recomposer now working.

The tree recomposer is now working. Some things still to be figured out,
such as if we need to set symbols in TypeTree (i.e. see doc also, as
it is an UnsupportedOperation).
Merge branch 'master' of https://github.com/aghosn/persistence

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