Wrote ManagerInterface, implemented it in RoomManager

ManagerInterface is a server-side pure abstract class; all of it's methods
are defined as pure virtual methods, and as such should be defined in the
derived classes. It works correctly along side the Singleton class, but
does not implement it directly as originally planned. It should also
support variadic parameters, which still need testing.

I've implemented ManagerInterface in RoomManager, but I've also disabled a
number of the RoomManager's features, including the lua interface. The
project as a whole should build, but it won't run correctly. The variadic
parameters will be tested using the other managers.

It feels good just playing around instead of pushing forward all the time.
Implemented ManagerInterface in AccountManager and CharacterManager

ManagerInterface was already designed for those two anyway. The only thing
left to do is to rewrite the room API, and the whole thing should work
fine again.

I still think map data should be saved and loaded by lua code, so the
rooms will still implement lua hooks. There may be other things that can
be loaded from SQL, but I don't know what.
finished rewriting the room API
Merge branch 'fun-with-interfaces' into develop