v1.1.1: Merge pull request #44 from theochem/update_readme2

Update README.md by adding the ChemRxiv information

v1.1.0a1: Merge pull request #43 from theochem/new_data

Add new external dataset

v1.1.0: Merge pull request #43 from theochem/new_data

Add new external dataset

v1.0.0a1: Merge pull request #42 from theochem/update_readme

Clean up README.md

v1.0.0: Merge pull request #42 from theochem/update_readme

Clean up README.md