parser name scanner: support classes without namespaces

We need to know the exact symbol that is used.
The leading \ is also part of it.
Added FQN support for PhpName::change
fix class names: prefix with \
always use full qualifed name (starting with \) for fixclassnames
added TC for introducing namespaces
Fix: also add (unneccessary) use statements for non-namespaced files. this will help to prepare them for namespaces

- fixed last use statement line