Initial Pull Request

This is the an initial pull request to set up peacecorps-site, and start a donation payment form. It's got a lot of things missing, but in the interest of having digestible pull requests I'm submitting this one. 

This still needs: 

* A better README
* More tests
* A country related field on the form
* Better form validation. 

But the rest of it should be ok, and is ready for review. 
Obviously not important, but there's a `self.assertTrue(form.is_valid())`