Kill off "Method 2" from bootcamp_graphics notebook

[cc7768]

This is not a particularly useful way to make plots in my opinion. I'm happy to hear otherwise, but I vote for killing off the section about using plt.plot as a way to generate plots.

[sglyon]

I also don't like it -- but there are a lot of resources on the internet that use it. I left it in up until now so that students will have seen it before