Move clarifications on donations to the FAQ.
Change copy-writing and structure of campaign page.

Includes a much more promiment call to action and some rewritten
copy on the purpose of Rails Girls Summer of Code.
Move date to June 7.
Make link to /campaign say "Donate Now!"
Merge pull request #39 from roidrage/mm-revamp-faq

Improve copy and the campaign page to have more explicit calls to action