Implement molecular surfaces

[tpfto]

I am planning to eventually have MoleculeViewer support the plotting of various molecule-related surfaces, like the solvent-accessible (Lee-Richards) and solvent-excluded (Connolly) surfaces, as well as electrostatic potential surfaces and molecular orbitals down the road. These represent a fair amount of nontrivial effort (ContourPlot3D[] is often too slow for plotting these), and the algorithms for implementing these efficiently are not that straightforward to do in Mathematica.