Support geometry and TCS shaders
Add fullvalues option: ply filenames are listed explicitly, and do not use the <timestep>-<iso> nomenclature. Add cutplanes option with two parameters: nearcut, farcut. Add CuttingPlane value to menubutton. If enabled, the button will provide a cutting plane which moves smoothly between neacut and farcut and back. Support http(s) based config files. Use two-faced normals in iso shader. Send 'A' for selected atom in multiuser mode. Add optional chain affiliations to atoms (chainfile option).