Shrimp Shader Generator FLTK2 GUI (SVN)

Updated light blocks so that the user can toggle custom lights as nondiffuse/nonspecular. Updated root block source so that light shaders have a default output uniform float __nondiffuse/__nonspecular shader parameter, which the blocks override. Updated the glass shader block and the function, so that it returns both color and transparency - transmission based shadows based on Alan Warren's port of the VEX shader by Mario Marengo.