Admin controllers

This PR has a higher-level (basic) redesign of most admin controllers, to object oriented controllers, and a few rewrites of methods. It should work as it is, because it's mostly only renames (and almost no moves! :P), in preparation for the MVCish code design we target.

I'm not sure we want it in as it is, since some aspects are very basic. On the other hand, I support it anyway because I took the slower route in order to keep things working easier, so I'd just consider it a stage of sorts.
Note: the issue of forwarding directly to actions is still unsolved in this PR, updates of the menu and dispatching mechanism will be necessary for that, apart from more fully OOP controllers. (more than this)