Add easy way to set and access "global variables" from the editor

[KVonGit]

My method when porting games with global strings and integers is to create a quest_global object and use that as the de facto window object.

I don't use the editor controls to add scripts, so I've never created any editor controls for this, but it should be relatively easy to create a few to allow using an attribute name alone to manipulate things.

(This should also include a function and editor controls to easily manipulate integers, using the second parameter like ASL does with set.)