cody: lvlgraph: hidden nodes

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@40392 4005530d-fff6-0310-9dd1-cebe43e6787f
cody: lvlgraph: highlight edges along hidden nodes

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@40393 4005530d-fff6-0310-9dd1-cebe43e6787f