Unfinished HFine functionality

[patrick-austin]

As noted in #83, the ChargeDistribution.HFine function is unused in any of the commandline functions. Based on discussion with @leandro-liborio this was likely the start of an effort to observe quantum effects occuring when replacing a H with muon in materials containing for example organic radicals. This will have an (averaged) effect on the hyperfine interactions.

If this is a desirable, feature, this code should be fully analysed and development of this feature continued.