Review notebooks for errors

[jGaboardi]

Following the correction of rendering errors (#16), ensure that notebooks are actually functional.

• [ ] 4d_distance.ipynb
• [ ] Example_NYCBikes_AllFeatures.ipynb
• [ ] NYC_Bike_Example.ipynb
• [ ] New_DistanceBand.ipynb
• [ ] ODW_example.ipynb
• [ ] OD_weights.ipynb
• [ ] autograd_test.ipynb
• [ ] dispersion_test.ipynb
• [ ] glm_speed.ipynb
• [ ] local_SI.ipynb
• [ ] netW.ipynb
• [ ] sparse_categorical.ipynb
• [ ] sparse_categorical_bottleneck.ipynb
• [ ] sparse_categorical_speed.ipynb
• [ ] sparse_grav.ipynb
• [ ] sparse_scipy_optim.ipynb
• [ ] sparse_vs_dense_grav.ipynb
• [ ] test_grav.ipynb
• [ ] validate_gravity.ipynb