Rewrote MLP calculations to improve efficiency by precalculating terms dependent only on u_0/u_2 and terms that appear in several calculations .  This rewriting also included calculating polynomial equations using Horner's method which turned out to be more accurate in addition too faster.  This version still includes a scaling factor on voxel updates to attempt to correct for the innapropriately large RSP values for voxels near the boundary due to the fact that these voxels are updated more often.  This scaling factor is sqrt(bi) bounded below by 1.0, preventing the update from being too small.