add 2 features to TProfGrid

need 2 new features added to TProfGrid (source code attached) 1. a new option is added: pgoSizeTrains 2. when the user shift-clicks a cell, all adjacent non-void cells that are in the current grid row and have the same Value and CustomData as the current cell (what we call _a train of cells_) should be selected 3. a frame is drawn that encloses the train of cells 4. the user should be able to increase/decrease the train by moving the lower/right vertex of the train frame. It would be nice to see that the cursor takes a new shape during this operation. When the train size is increased by 1, the next right cell in the current row takes the same properties of all the cells in the train. When the train size if is decreased by 1, the cells that were part of the train (and are no more part of the train) are emptied. 5. a new option is added: pgoDragTrains 6. see point 2. 7. see point 3. 8. the user should be able to drag the train to different positions in the grid. New events OnTrainDragDrop and OnTrainDragOver manage the dragging operations. 9. during dragging, the train frame should move so that the user clearly sees where the train is placed 10. during train drag mode, the standard events OnDragDrop and OnDragOver should be disabled. 11. new events OnTrainDragDrop and OnTrainDragOver should pass needed info re the train that is dragged