Fix environment.yml

Install prody with conda and not pip.

Various bugfixes

* Ensure we calculate rotatable bonds on the version of the ligand with no hydrogens. Also fix spelling of rotable -> rotatable. Closes GH-220 (@Nobody-Zhang)

* Vectorize SO3 calculations. Closes PR GH-218 (@tornikeo)

* Pin pytorch-lightning version. Closes GH-193 (@mikael-h-christensen)

* Guard against divide by zero in torus.py. Closes GH-161 (@amorehead)

* Update e3nn version to 0.5.1. Closes GH-155 (@amorehead)

* Add a little more info on docker container to README.md

Improve memory efficiency of graph convolution operation.

Add examples

Update README.md