Translation-Rotation internal coordinates, OpenMM calculator, Relaxed scans

Addition

• Geometry loading from pubchem via pubchem:[name], e.g., pubchem:thymine or pubchem:methane
• Growing Newton Trajectory (experimental) as described in 10.1063/1.1885467
• Enabled TRIC for improved optimizations of solvated and/or non-covalently bound systems (see 10.1063/1.4952956, coord_type: tric)
• Calculators for preconditioning of translation and rotation described here 10.1002/jcc.26495, useful for docking and preparing input geometries for COS methods.
• Driver for 1d relaxed scans in internal coordinates (keyword scan). See 8. Relaxed Scans in the documentation
• Basic support for reading & writing CHARMM coordinate card files
• OpenMM calculator using ParmEd

Bugfixes

• Improved parsing & writing of PDB files
• Post-HF Psi4 calculations returned only HF energy

Miscellaneous

• Refactored RedundantCoords and updated pysistrj --internals
• ONIOM calculator now uses sparse matrices for calculations involving the Jacobian