Scrub

Let me know what you think! @mohit @jonahkagan 

(this is going to branch pr_onto because my first few commits went to master and so you wouldn't see the full PR. Once we merge this to pr_onto we can set it as master)
do you think this section is necessary? it's kind of saying "if this library doesn't have the functionality you want, write your own code," which doesn't really need to be said