[Decide] Re-insert two small paragraphs which were removed for space reasons

[davidlmobley]

This PR is to either re-insert or decide to discard two paragraphs which had to be removed for space reasons prior to submission of the paper:

One which speculates about potential water sampling problems in lysozyme by saying:

Potentially, water sampling could also be a challenge in the polar binding site, as phenol binds with one ordered water~\cite{wei_model_2002} but to our knowledge, timescales for water sampling have not yet been examined, other than noting that water does not enter the polar binding site as ligands are removed~\cite{boyce_predicting_2009}. The apolar cavity is dry both with ligands present and with empty, so water sampling in the there cavity seems unlikely to be a challenge.

The PR proposes adding this back (it's commented out), but alternatively we should just discard it.

The other case relates to host-guest systems and deals with why OA might not appear to have major force field issues yet:

The challenges of system definition and conformational sampling appear to be greater for OA and TEMOA than for CB7, so evidence of force field limitations, if present, is not yet as clear. There have been some comparisons of charge~\cite{mikulskis_free-energy_2014, muddana_sampl4_2014, monroe_converging_2014} and water models~\cite{yin_sampl5_2016}, but differences so far seem mostly inconclusive or at least not that large. Similarly, OPLS and GAFF results did not appear dramatically different in accuracy~\cite{bhakat_resolving_2016}

If we don't want these, they should be removed from the LaTeX of the current paper, where they are currently commented out.

[davidlmobley]

Incorporated via #20