/fill command adaption

So basically it's an adaptation of the standard fill command except it rounds off the corners of fill area. The center point coordinate should be a seperate input to allow the making of oval, egg, or oblong shapes. the command for a ball would look something like this: /fill_radius 0 0 0 20 20 20 cobblestone [C= 10 10 10]. While an egg shape would be something like: /fill_radius 0 0 0 20 20 20 cobblestone [C= 10 3 10]. This command is to ease the construction of large circular structures such as craters or snow globes.