Grids: implement goIgnoreRowContentForAutoAddRows option.
If set then AutoAddRows will add a row even if last row is empty.
The then added row will not be removed if it is empty when user moves the cursor up.


git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@39940 4005530d-fff6-0310-9dd1-cebe43e6787f