improve proof of isprop_biinv
Fixing HProp
more capitalization
Merge branch 'pull-request-2' of https://github.com/DanGrayson/HoTT

Fixing Conflicts:
	theories/Equivalences.v
	theories/HProp.v
	theories/Overture.v
Merge branch 'upstream' into eqvar

Conflicts:
	theories/EquivalenceVarieties.v
	theories/Equivalences.v
	theories/Trunc.v
Reorder notations so Coq displays { & } rather than "exists"
Merge branch 'master' of https://github.com/spitters/HoTT into upstream

Conflicts:
	theories/EquivalenceVarieties.v
	theories/Equivalences.v
Fix naming inconsistency
shorten one proof, make 'idmap' an abbreviation