Chris matplotlib pandas mods

Here are all the changes that I made to the readwrite and matplotlib tutorials. I have also included the "empty" notebooks with most of the input code removed (but with comments retained).  I also cleared the output on both styles of notebooks.

Let me know if this looks OK, or if you wanted me to PR against a different branch/repo.

Also, thank you thank you for covering this.  I really appreciate it (and presumably so do the people who won't get sick because of me :P )