CPTableView: force the mask to CPViewNotSizable for IB made CPTableCellView.
Added documentation for tableView:dataViewForTableColum:row: delegate method. Document other cases, when we expect the data view to have a CPViewNotSizable mask.
ViewBasedCib example: added variable row heights.
Merge pull request #1815 from cacaodev/CPTableView-issue1814

CPTableView fix for #1814.