v0.1.2

This version includes the following changes:

• Fixing the computation of metrics during training, by reweighting the metrics of
  each batch to account for a varying number of real graphs per batch; this results
  in the metrics being independent of the batching strategy and number of GPUs employed
• In addition to the point above, fixing the computation of RMSE metrics by now
  only computing MSE metrics in the loss and taking the square root at the very end
  when logging
• Deleting relative and 95-percentile metrics, as they are not straightforward to
  compute on-the-fly with our dynamic batching strategy; we recommend to compute them
  separately for a model checkpoint if necessary
• Small amount of modifications to README and documentation