Laying out new material
Starting beginner's lessons on Python
Second beginner's lesson on Python
Third beginner's lesson on Python
Fourth beginner's lesson on Python
Renaming file to be consistent with hyphenation convention
Final two lessons on Python (still need challenges)
Removing .pyc files when cleaning
Updating based on feedback from @jdblischak
Adding challenges to the last two notebooks in the series
Updating based on feedback from @ahmadia
First three lessons on SQL for beginners
More database lessons for novices.  To do:
*   `group by` in aggregation
*   data hygiene
*   explain the `%%sqlite` magic
1. Filled in 'group by'.
2. Put data hygiene in discussion of joins.
3. Got rid of 'next steps' sections.
Cleaning up before submitting pull request
Merge branch 'master' into new-sql-beginner-lessons
Merge branch 'master' into new-python-beginner-lessons
Moving assertions and unit testing to intermediate; not sure what to teach about defensive programming here
Material on QA from novice for recycling
Re-introducing unit testing