Allow multiplication of double point by scalar

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@41849 4005530d-fff6-0310-9dd1-cebe43e6787f
Initial implementation of diagrams

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@41850 4005530d-fff6-0310-9dd1-cebe43e6787f