Reorganization of artfiles

A little bit of housecleaning…
-Travis
Updated Grass Tiles

Grass tiles now have a middle-corner piece to connect double slope
pieces.
Added Dirt Tiles

Created a very simple dirt tile based off the grass tile to give us more
of a variety of pieces to use. WIP-half grass/half dirt so the
transition between pieces are smoother.
Transitional Pieces

And other minor changes to the dirt tiles.
-Travis
Grass Single Tiles!
Dirt Singles

More Yay!
Grass and Dirt Slope Tiles

ERMAHGERD!
Addd GRASS-TILES to zero

Hopefully they work well.
-Travis