Fixed a problem with the Lafortune model, that was using only results from the last lobe. Added the "pump-up" factor suggested by Attila Neumann to the Lafortune model (defaults to original results with p = 0). Added anisotropy support to the coefficients data. Added 29 materials's coefficients, including data from Tek2Shoot's T2SFilePack for Columbia-Ultrecht CURET BRDF database, and some Cornell Universy Program of Computer Graphics ASTM measurements. Changed the usage information accordingly.
