Relax constraints on methods unicity

They are not viable in case of explicit method calls.
As a side effect, test all dispatched method calls both as explicit call
or method calls.
Suppress __classname__ horror

Classes are now proper and regular members of their parent module, no
need for the __classname__ trick horror.

Many ugly hooks are suppressed here and there thanks to this cleanup.

Huge thanks to Pierrick for his preparatory work!