Zero-radius atoms should not contribute to molecular surface

[sobolevnrm]

Hello --

srfm mol and srfm smol will generate surface contributions from zero-radius atoms. They probably shouldn't do that but that's a low-priority bug to fix.

What are you trying to accomplish with the dummy atom? There may be other ways to get the information you're looking for.

Thank you

Originally posted by @sobolevnrm in #186 (comment)