Improve Console Commands

[rgrieder]

There are currently some issues and missing feature with console commands. I would like to compile a list here that can be discussed and modified:

1. Activity: Console commands should have the possibility to be active/inactive
2. Lifetime: Console commands should be more dynamic so you can create and destroy one at will (and avoid memory leaks).
3. Accessibility: Console commands should have access permissions.
4. Dispatching: What about console commands that can be applied not to one single static function but to all objects of a member function? It would be almost like the config values but with 5 possible different arguments and no ini-file entry.
5. Preconditions: Is it really necessary that all classes using CC must derive from OrxonoxClass? It is of course mandatory for 4.

There is already some basic construct to realise accessibility but it is not yet implemented. I think this might be quite important because sometimes these console commands ease programming by magnitudes if you want to avoid some singleton-hacking or so.

Btw: I assigned the severity of the ticket "critical" because we currently have memory leaks due to console commands.