grassenergy.8x6 contains palette information

[montoyaaguirre]

This file, unlike the rest of the files in this folder contains the palette information.

[xCrystal]

Done, thanks for pointing out! Eventually, it may be preferable to have the actual color in the pngs (by combining information from the .2bpp and .pal files), but meanwhile I removed it from grassenergy for consistency with the rest of the cards and other graphics.