Move ObjectClassifier and UniverseLevel out of types/
delete contrib/V.v (now it's in hit/)
also change the pointers in HoTT.v
fix pointers to moved files
Merge pull request #480 from mikeshulman/move

Move ObjectClassifier and UniverseLevel out of types/
uniformize reflective subuniverses and modalities
truncation is a modality
Clean up Pushout.v a bit
join
open and closed modalities
better naming for equivalence move functions
explicit Existing Instance *and* Coercion after typeclasses, for clarity
coqdoc comment
remove unnecessary imports
clarify comment about generalizing binders
comment about Local Instance
use Local Instance in PropositionalFracture
use Local Instance in Truncations
comment about _equiv naming
Typeclasses Transparent inO