Case sensitivity of CBFV on Linux/WSL

On WSL, a problem is encountered in notebook 3 when running this line of code:

```
X_train_unscaled, y_train, formulae_train, skipped_train = generate_features(df_train_sampled, elem_prop='oliynyk', drop_duplicates=False, extend_features=True, sum_feat=True)
```

My error message is the following:

```
FileNotFoundError: [Errno 2] File /home/janash/projects/materials-project-bp/notebooks/cbfv/element_properties/oliynyk.csv does not exist: '/home/janash/projects/materials-project-bp/notebooks/cbfv/element_properties/oliynyk.csv'
```

I've concluded that it has to do with case sensitivity of the path. In the repository, the folder is titled uppercase `CBFV`, while the path in the error message above is lowercase `cbfv`. If I change the folder name to lowercase, I am able to run the line of code without an error. This does require changing the imports though (ie `from CBFV.cbfv.composition import generate_features` becomes `from cbfv.cbfv.composition import generate_features`).

I've checked this on Windows and the case sensitivity is not an issue on that OS.