Shrimp Shader Generator FLTK2 GUI (SVN)

Improved compatibility with Aqsis and Pixie. Rtglass block needed alternative implementation of glass, since Pixie seems to have problems with binary conditionals.

Updated compatibility with Aqsis.

Improved compatibility in all potentially problematic blocks. Fixed typo in raytraced glass shader (missing internal reflections). Updated all shading functions, distributions, and blocks for parent dependency. Added options to control the Voronoi noise in the blotches block, fixed potential division by 0 in gamma block. Improved raytracing blocks for per implementation cases.

Fixed another problem in shader invocation for prman.

Fixed potential shader compiler invocation problem with prman.

Updated the Lafortune block for 2 coefficients.

Added Mario Marengo's complementary/error function, and removed the C shadeop. Added the Schlick anisotropic specular term, and updated the remaining BRDF blocks.

Updated typo in distributions. Complementary error function will be replaced later.

Updated the Trowbridge-Reitz distribution. There is a normalization term (we'll have to use a constant for the time being, until i gather more info on this - the paper is hard to find).

Updated distributions header to fix a typo in trowbridge-reitz PDF.