Adding icons 'Select' and 'Fill'.
Add multi_selection property to RoomEditor.
Starting to diplay the selection.
Changing selection icon.
Adding components for multiple selection in preferences.
Addind new properties into preferences.
Use values stored in preferences to draw selection.
Apply snapping to the selection origin.
Apply snapping to selection dimension.
Implementing fill function for objects.
Adding filling for tiles.
If the multi selection mode is set to off, reset the selection.
Test that the cursor position is inside the room.
Starting to implement the delete.
Delete tiles.
clean-up.
Adding snap to grid icon.
Apply the snapping, when the snapping button is activated.
When filling a region, take into account snapping.
Adding 'Add on top' button.