Allow for Project Level (.DME) filtering of Objects in Object Tree

[Rockdtben]

Allow for a BYOND project to determine things that should now show up in the Object Tree.

There are certain objects that shouldn't be placed on a map and do nothing. This feature should allow a project member to write a text file that provides a "VARIABLE" : "VALUE" pair that defines items that should not show up in the map editor. mapEditor:0

Obj/Spirit/Don'tShowMe
var mapEditor=0

FastDMM would filter out all objects with mapEditor=0... as an example.