Add modified intro python lesson

[aays]

This version of the lesson is largely based on Madeleine's, save for a few minor differences in the first half.

At the end, I've added some brief seaborn, and also use sns.load_dataset to load in a built-in dataset instead of having participants download a file.

[QuLogic]

Checking type(x) == int really should be isinstance(x, int).

[QuLogic]

Also, no spaces around function keyword arguments; this isn't R.

[aays]

Thanks - notebook's been updated to reflect the feedback.

(and spaces around arguments removed... curse you, PEP8!)

[QuLogic]

I'm not sure if you are going to mention PEP8, but for docstrings you can also mention numpydoc or google docstring styles. Both are supported by sphinx's napoleon extension and are less verbose than sphinx's default reST. With sphinx, you can make nice HTML docs from your code. (You don't necessarily need to mention all this of course.)

[QuLogic]

BTW, I tried this out on someone who just installed anaconda and %matplotlib inline didn't seem to be necessary. I think soon we won't need to recommend this.