Validate log volume moves implementation

[emarinri]

Is your feature request related to a problem? Please describe.

There is code that was implemented a while back related to performing volume moves in log space. As far as I can tell, the code looks good, but has not been used in a long time. Cassandra has changed a lot since then, so probably it would be good to validate this implementation and incorporate it as a feature.

Describe the solution you'd like

Validate using NPT and GEMC-NPT. As far as I remember from Frenkel & Smit and/or Allen & Tildesley, doing volumes in log space would speed up convergence.