Fix numerical precision issues in Fresnel code
Fix numerical precision issues in Fresnel code

appleseedhq/appleseed,appleseedhq/appleseed,est77/appleseed,pjessesco/appleseed,pjessesco/appleseed,luisbarrancos/appleseed,pjessesco/appleseed,dictoon/appleseed,dictoon/appleseed,pjessesco/appleseed,luisbarrancos/appleseed,Vertexwahn/appleseed,est77/appleseed,dictoon/appleseed,appleseedhq/appleseed,appleseedhq/appleseed,pjessesco/appleseed,est77/appleseed,Vertexwahn/appleseed,luisbarrancos/appleseed,est77/appleseed,Vertexwahn/appleseed,luisbarrancos/appleseed,dictoon/appleseed,est77/appleseed,appleseedhq/appleseed,luisbarrancos/appleseed,dictoon/appleseed,Vertexwahn/appleseed,Vertexwahn/appleseed