Bug fixing and glDrawCell change

glDrawCell now works as intended, drawing the correct cell and using the
parent relief class that is given.
Change to glDrawCell parameters:
glDrawCell(cellw, cellh, column, row, x, y, imageWidth, imageHeight,
parentWidth, parentHeight, parentX, parentY, intensity, diffuse, normal,
relief, emissive, parentRelief, light1, light2, light3)