Updated for changes in Zenodo

• Zenodo updated and made small changes to their API, which required changes in SEAMM.
• Consolidated all private information about the user and their keys for Zenodo in ~/.seammrc

Added more unit conversions to support thermochemistry

• added E_h/K --> kJ/mol/K

Adding units to support Buckingham potentials

Merge pull request #50 from molssi-seamm/dev

Adding units to support Buckingham potentials

Add Compact JSON Encoder

Added a Compact JSON Encoder to make schema-like JSON more human-readable

More conversions involving substance (mol) to number

• Added energy/mol/Å^2 --> energy/Å^2 for force constants
• Added energy/mol/Å^3 --> energy/Å^3 for stress/pressure/elastic constants

Improvements to unit handling.

Merge pull request #46 from molssi-seamm/dev

Added default units for elementary charge (e).

Improved handling of grids of plots

Gave control over spacing between plots in grids.

Added elemental data

Added elemental densities and electron configuration to support DFTB+ and use of Vegard's law or similar approximate methods for cell volume.

Loosened need for Zenodo log-in

Only needed is uploading flowcharts.

Control over which database to use.

Added a --database flag to give which database to use. Defaults to ./seamm.db. Also added a --read-only flag.