Update clutz README with minimal docs.
Update clutz README with minimal docs.

Reviewers: rkirov

Reviewed By: rkirov

Subscribers: typescript-eng

Differential Revision: https://reviews.angular.io/D137

rehmsen/clutz,angular/clutz,polybuildr/clutz,rehmsen/clutz,angular/clutz,angular/clutz,rehmsen/clutz,polybuildr/clutz,dpurp/clutz,polybuildr/clutz,dpurp/clutz,dpurp/clutz