Shrimp Shader Generator FLTK2 GUI (SVN)

Added some fixes and comments to the Cook-Torrance model, and the microfacet distributions and shadowing/masking functions in their respective headers.

ENH: experimental array support (without the message passing stuff)

- fix scene menu duplicate entry,appear after access to file/options dialog

-Add number of blocks listed in the doc

FIX: array support level 1 completed

ENH: moved array value declarations to the local variables

FIX: array valued variable replacement now works properly

-Add default credits informations to xml and xsl files
-Add <rsl_link></rsl_link> support in the doc system of url for block usage.So just add in each block in the usage section a new element call <rsl_link> it will be transform to a url link.
-Change Lafortune and Fur block usage to support <rsl_link>

Fixed wrong range in Lafortune model description tag.

Fixed the Ward anisotropic sampling. Cleaned up and hopefully improved a bit the performance of the Ward isotropic, Ashikhmin-Shirley anisotropic sampling, and the Beckmann microfacet distribution.