- Fix wrong order in printing of universe inconsistency explanation
- Allow coercions between two polymorphic instances of the same inductive/constant.
- Do evar normalization and saturation by classes before trying to use program coercion
  during pretyping.
- In unification, force equalities of universes when unifying the same rigid head constants.
- Fix omission of projections in constr_leq
- Fix [admit] tactic's handling of normalized universes.