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)
I tried to explain it better.  d1285dd
Strings are nice and easy - I think it is good to have them.
This is a better way to support them though. Has been implemented. 3e3f977