Files referred to in example_configs don't exist

[PatWalters]

example_configs/logp_gcnn_config.py refers to
./benchmark_datasets/Lipophilicity_dataset/Lipophilicity_train.csv
./benchmark_datasets/Lipophilicity_dataset/Lipophilicity_test.csv
This directory doesn't exist, the directory should be
benchmark_datasets/logp_dataset
In addition, the dataset in this directory is not split into train and test.