clipping the lighting result via ciel was causing banding issues with specular maps with alpha channels. rev2. also addresses the warning:

"warning X3571: pow(f, e) will not work for negative f, use abs(f) or conditionally handle negative values if you expect them" since it was coming from the same line
Merge pull request #591 from Azaezel/clubbing_ciels

revised #568. abs and max.