Add offline emulation for doors and secret exits

[Sebster7]

It would be really nice if for offline emulation, one could interact with doors and secret exits, and they were initially closed. This would, for people using it, enable people to learn areas better and improve their door handling skills without risk. So open and close exit would work (for non-hidden exits), and also with the name of the exit.

[nschimme]

I suppose we could assume that all doors are initially closed (we don't technically store default open/close door state in the MM2 database).

[Sebster7]

I suppose we could assume that all doors are initially closed (we don't technically store default open/close door state in the MM2 database).

Yes, and most of them are.