Rewrote maploader to act faster and better handle set variables (a.k.a basically reimplemented BYOND map parser to load DM maps at init or in-game).

Most notably :

* better loading times, less processing loops, got ride of the old_turf checking, since we're building the map on area/turf/space
* lists variables are now taken into account (simples and associatives)
* every character can now be used inside a string without fear of breaking the loading process (before using ; could mess the whole thing up)
Merge pull request #1808 from Menshin/Bleeding-Edge

Maploader rewriting, /vg edition