Safe_library : a record type for compiled_library instead of large tuple

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16374 85f007b7-540e-0410-9357-904b9bb8a0f7
Safe_typing+Libary: use some arrays instead of lists in vo structures

 Very little space saved this way, but it would hurt either...

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16375 85f007b7-540e-0410-9357-904b9bb8a0f7