Better treatment of constants
Better treatment of constants

- separate datatypes for type and expression constants (fixed sets)
- expression constants include integers and locations
- fixed total mapping from type constants to their kinds
- fixed total mapping from expression constants to their types
- the signature is basically just these two fixed mappings now
- we can prove once and for all that the types we give to our
  expression constants are well-kinded in any typing context

hoheinzollern/FStar,FStarLang/FStar,hoheinzollern/FStar,aa755/FStar,MallabaevAzamat/FStar,MallabaevAzamat/FStar,FStarLang/FStar,FStarLang/FStar,YaccConstructor/FStar,hoheinzollern/FStar,msprotz/FStar,msprotz/FStar,aa755/FStar,A-Manning/FStar,MallabaevAzamat/FStar,A-Manning/FStar,msprotz/FStar,hoheinzollern/FStar,YaccConstructor/FStar,MallabaevAzamat/FStar,msprotz/FStar,YaccConstructor/FStar,YaccConstructor/FStar,aa755/FStar,aa755/FStar,A-Manning/FStar