renamed SystemTransformer to DartemisTransformer because it'll transform more than just the systems (otherwise I'd have to parse the content several times to create the CompilationUnit, which isn't the fastest thing in the world)
create instances of Mappers in Managers
create instances of Managers in Systems and other Managers
System instances are assigned in Managers and other Systems
updated documentation, deprecated the mirror world, updated example to not use mirrors