add a few type theorems to regex-ui

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2265 303c5b2c-9740-0410-b014-fd8f9db7be32
add (prelim) last-theory-change utility

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2266 303c5b2c-9740-0410-b014-fd8f9db7be32