cleaning up the color interface by adding FloatColor. FloatColor will be
used by DepthGraphics to interpolate colors.
removing unuseful classes in com.nerius.grafx which made dependency on
com.nerius.grafx.img. now, com.nerius.grafx has no dependency on any
package that is not part of standard java-1.0. Rasterizor and
AnimatingRasterizor have been removed.