the modal factorization system
prefix O_inverts with redundant "Local"
add ev_equiv tactic to evaluate equiv_compose' etc.
Conform to naming conventions a bit better
also rename in HoTTBookExercises
Merge pull request #591 from mikeshulman/biinv-naming

Conform to naming conventions a bit better
Make [path_induction] more robust

In newer trunks, it'll loop on section hypotheses.  See
https://coq.inria.fr/bugs/show_bug.cgi?id=3769.
improve lift and lower
comment about universe annotations and cumulativity
add a test for Lift'
Merge pull request #595 from mikeshulman/lift

improve lift and lower
Merge pull request #589 from mikeshulman/modal-factsys

The modal factorization system
Merge pull request #594 from JasonGross/robust-path-induction

Make [path_induction] more robust
PathSplit maps as another variety of equivalence
Use pointwise pathsplitness in reflective subuniverses
build repleteness into UnitSubuniverses
start the recursion in PathSplit at a more sensible place
add universe annotations to modalities etc.
some more useful lemmas
collect Extensions in their own file