Translator demystified

The translator class is now much better readable as things are cleaned up heavily and function parameter are named now. No mystery anymore what to feed in.

All translations are now now done by ``__()`` and a default return value (other than the key if no translation is found) and transChoice is now transparently done by adding a ``DEFAULT`` or a ``NUMBER`` key/value pair to the parameter list.

Contenttype translations ar now again done in ``translation`` => ``generic translation`` => ``fallback`` order.

PT translation files updated.

Also a few bugs were fixed.