Molecule 2.20

See CHANGELOG.rst for full details

Pre-release

Should be functionally correct

Release a python dist package with fixed README

Pre-release

Added important changes to 2.19 release

bumped for release of 2.18.1

one more bump for release of 2.18

bumped for release of 2.17

bumped for release of 2.16

bumped for release of 2.15