Yaocho APIs

This adds a few APIs that were useful for Yaocho. These need to get to prod before I can put Yaocho in the marketplace.

r?
That's about right. DRF parses number for us, as far as I can tell, so request like `/foo?is_template=1` or `/foo?is_archived=0` will work. I don't think any thing the user can send in will be dangerous to us, it just might not work (for example `/foo?is_template=false` would be the same as `/foo?is_template=1, since "false" is truthy. 

It's probably worth figuring out some way to transform these values nicely into real True and False values, but I think that it is ok for now.