Added output for viewing the structure in the Dashboard.

Added code to output a form of MMCIF acceptable to the NGL viewer, so that we can use it to view structures in the dashboard.

Rigid waters

Added capability to handle rigid water molecules and various water models.

Added plotting capabilities.

Consolidating a number of changes, but the noticeable user visible change is the addition of Plotly plots, which are currently used in LAMMPS.

End of 2019

This release contains the fixes for the "Cancel" button problem, wherein clicking Cancel did not update the GUI.

Yet another intermediate release, with configargparse

0.6

Fixed formatting errors, and wrong path in _version.py.