IDE: unit deps: popup menu item for unused units

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@41922 4005530d-fff6-0310-9dd1-cebe43e6787f
IDE: unit deps: clean up

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@41923 4005530d-fff6-0310-9dd1-cebe43e6787f