Rewrote README.md and added the examples from the PyData 2013 preso by Elias

RFC: let me know if this makes sense.

Updated pictures to use the new visualizer, except the big splashy dep graph which I'll do later.

Removed some crap in examples/ and doc/ and added some more random stuff to README.md
Merge pull request #143 from erikbern/new-doc

Rewrote README.md and added the examples from the PyData 2013 preso