Open Principal Odor Map - beta

This is first pre-release of openPOM library.
The release includes:

• Graph featurization class
• MPNN-POM model class and required layer classes
• Notebooks for Leffingwell and Goodscents dataset curation
• Example notebooks for model training and fine-tuning
• Benchmark notebooks with ensemble scripts

The library is also released at pypi: https://pypi.org/project/openpom/