[WIP] remove rewind

Removal of `rewind` in `TypifiedElementCollectionProxy` and added a test to show, that current is not working properly on Collection Proxies. Same for `reset`, `each` ... 

Maybe this shouldn't even work for `ArrayObject`because it forces an `array`but after all its still working.


Closes #80 
Test doesn't really assert any useful stuff. Of course key `key($this->element)` will be 0 at all times, because adding elements to a collection doesn't even touch the iterator.