fix: corrected mu vs muD usage, remove packing fraction option #198
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closes #188, closes #187
Docs update for this PR is tracked through docs: update documentation to reflect changes in the CLI structure and mud computation #192.
Here's a screenshot of the GUI:

From the screenshot here I think I like keeping all chemical info in one argument instead of separating it like
-s NaCl -e 10 -d 1.5 -c 1.0for composition, energy, density, and diameter. I can separate arguments for "getmud" subcommand though, if this is easier for CLI users. Thoughts?@sbillinge ready for review.