Merge pull request HoTT#1443 from andreaslyn/infinitary-universal-alg…

…ebra

Term algebra and congruence

Merge pull request HoTT#1431 from Alizter/makefile_fix

modified _CoqProject so that it works with coq_makefile

Merge pull request HoTT#1413 from Alizter/8.13

update to V8.13

Merge pull request HoTT#1374 from Alizter/8.12

Update to Coq V8.12

Merge pull request HoTT#1293 from Alizter/conjclean

moved Conjugation.v into contrib/old

Merge pull request HoTT#1110 from JasonGross/use-V8.10.0

Update submodule to Coq V8.10.0

Tag for Coq version 8.9

Tag for Coq version 8.8

Tag for Coq version 8.7

Tag for Coq version 8.6