Almost full engine rewrite. Only grammar & in-game hooking system kept.
* No script text interpreter anymore
* Scripts are statically compiled to an object AST
* Engine can evaluate the script's AST without reflection, and minimum
casting
* Script local variables are preallocated, but without scope awareness
yet (declare them all at top level scope for max efficiency)
* While loop added
* Boolean AND and OR added.
* Boolean constants true & false added.
* String constants can be used as local variables.