Enhancement of 3.resistance-signature/0.training-test-split.ipynb

[yhan8]

We dropped the inference set (batch 3) because of overly confluent plates and suboptimal plate design. In the notebook, I still need to output the bortezomib signature analytical set, but I can also include the new batches of data, which will serve as a better experimentally designed inference set as included in pull request #114