Move Fibrations.v out of Basics & add stuff using Types.Sigma
add more documentation for `simpl rewrite`
Merge pull request #587 from mikeshulman/fibrations

Move Fibrations.v out of Basics & add stuff using Types.Sigma
Merge pull request #588 from mikeshulman/rewritedoc

add more documentation for `simpl rewrite`
the modal factorization system
add base type to the is_mere_relation notation, close #586
prefix O_inverts with redundant "Local"
add ev_equiv tactic to evaluate equiv_compose' etc.
Merge pull request #590 from mikeshulman/mererel

add base type to the is_mere_relation notation, close #586
Conform to naming conventions a bit better
Merge remote-tracking branch 'upstream/master'
also rename in HoTTBookExercises
Merge pull request #591 from mikeshulman/biinv-naming

Conform to naming conventions a bit better
Merge remote-tracking branch 'upstream/master'
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 remote-tracking branch 'upstream/master'