composition with iso is weq
Merge pull request #25 from benediktahrens/master

composition with iso is weq
added version of weqimplimpl to hProp
Merge pull request #26 from benediktahrens/hprop

added version of weqimplimpl to hProp
improve INSTALL file
added 2 lemmas about inverse morphisms to precategories
added lemma assoc4 to first compose two middle morphisms of 4
Merge pull request #28 from benediktahrens/master

3 lemmas for precategories
Merge pull request #9 from UniMath/master

Update