Some improvements to the elaboration and star-transformation.
Some improvements to the elaboration and star-transformation.

- Allow Tm_meta to "pass through"
- Accept GTot in starred types.
- Improve error messages.

hoheinzollern/FStar,hoheinzollern/FStar,hoheinzollern/FStar,A-Manning/FStar,hoheinzollern/FStar,A-Manning/FStar,FStarLang/FStar,A-Manning/FStar,FStarLang/FStar,FStarLang/FStar