Shrimp Shader Generator FLTK2 GUI (SVN)

Added complex arithmetic blocks and complex Fresnel block (unpolarized light), using functions defined in odwikicomplex.h header, from the Odforce.net Odwiki, and the Odwiki BRDF article, by the Odforce community and Mario Marengo. Added respective header, odwikicomplex.h, updated shrimp_helpers.h for hyperbolic sine, cosine, tangent, instead of being defined in the their respective blocks bodies. Updated the trace() block for a typo and incorrect macro definitions and checks. Many thanks to once again, Mario Marengo, Jason, and the Odforce and Odwiki community.