add feature to level an area

[walterhiggins]

Another nice feature could be "level" which would essentially level a plane of a specified size, removing all blocks above and filling blocks below (if you e.g. want to level a field for a castle).

[nickarls]

If you really want to get fancy, after the plane has been created, one would loop down and out from the plane and place grass blocks where no block is present, stopping when there has been no blocks placed for an entire loop. The result would be a gradient (flat) hill that would melt into the surroundings