Shrimp Shader Generator FLTK2 GUI (SVN)

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.

Added the Strauss empirical BRDF to the local illumination models header, as well as the respective xml block.

Added the Banks fast anisotropic shading model block.

Added the Banks fast anisotropic shading model in the shading models header, and the respective block.

Updated shadingmodels.h to use the fixed Smith attenuation term in the Cook-Torrance model.

Updated distributions header to fix the Smith attenuation term (product of 2 attenuation terms, between incident vector and microstructure normal, and viewer and microstructure normal).

Implemented the Export Scene menu

Added tooltips to all the main window's widgets

Removed anisoct block, since it's included in new Cook-Torrance block.