Minor additions
Adding done tactic
Updated old library name in INSTALL.txt.
types/Prod: add the negative universal property
Merge pull request #70 from mikeshulman/prod

types/Prod: add the negative universal property
types/Unit
Merge remote branch 'upstream/master' into unit
Rename Empty_set to Empty, as discussed.
Make TAGS get made by default by "make", provided "etags" is present.
Merge branch 'master' of github.com:HoTT/HoTT
working on porting HSet
types/Prod: improve the UMPs
types/Prod: products are symmetric
Merge remote branch 'upstream/master'
remove an extra definition of HProp from Empty
Merge branch 'master' of git://github.com/HoTT/HoTT

Conflicts:
	theories/HLevel.v
	theories/HProp.v
	theories/HSet.v
Merge branch 'master' of git://github.com/HoTT/HoTT
added a few lemmas.  "cancel" now means "unwhisker".
Merge branch 'cancel' into sigma
types/Empty.v is done
Merge branch 'master' of https://github.com/HoTT/HoTT