Replacing lists by sets in clear tactic.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16734 85f007b7-540e-0410-9357-904b9bb8a0f7
Added a more efficient way to recover the domain of a map.

The extended signature is defined in CMap, and should be compatible
with the old one, except that module arguments have to be explicitely
named. The implementation itself is quite unsafe, as it relies on the
current implementation of OCaml maps, even though that should not be
a problem (it has not changed in ages).

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16735 85f007b7-540e-0410-9357-904b9bb8a0f7
Actually using the domain function for maps.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16736 85f007b7-540e-0410-9357-904b9bb8a0f7