add FAQs

[k8hertweck]

• Can you find the history of commands you've run in Jupyter notebook in the same way one might from the command line?
  • You can use the Jupyter notebook magic %history command
• If you had a data frame with named index values (as opposed to a range of integers), how would you refer to specific rows with the loc interface?
  • loc supports indexing by named index values. See the "Getting values" section of the pandas documentation for loc