Coqc: accept -exclude-dir + some others + cleanup (fix #3025)

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16430 85f007b7-540e-0410-9357-904b9bb8a0f7
Coqdep: add an -exclude-dir option (wish mentionned in #3025)

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16431 85f007b7-540e-0410-9357-904b9bb8a0f7
coqc and coqmktop migrated in tools/, get rid of scripts/ subdir

 No need to place these binaries apart, and anyway they aren't
 (shell) scripts since ages.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16432 85f007b7-540e-0410-9357-904b9bb8a0f7