factorization systems
add some universe levels
remove unnecessary number on issig
put Build_PathFactorization outside in pathfactorization_path
factor an opaque lemma out of path_factorization for a 2x speedup
Factor an opaque lemma out of lift_factsys, no speed difference
oops, both classes in a factsys must include all equivalences
Merge pull request #563 from mikeshulman/factorization

Factorization systems