New Python beginner lessons

1.  Lay out directory structure for new novice/intermediate lessons (see #121-#130).
2.  Add notebooks for novice introduction to Python, plus utilties, data files, and one image.
3.  Modify Makefile to delete `.pyc` files when doing `make clean`.
4.  Add a `NEW_MATERIAL.md` file that will eventually become the new `README.md`.