Update nginx.bash and jump to 7.

The jump from 6 to 7 happened because I was initially testing to
see if I should ship my verison of NGINX with mod_pagespeed but
that idea was scrapped because mod_pagespeed on Nginx does not
support inline rewrites so you end up with some fucked up
sources that just don't make sense if you plan to link
externally.
Cleanup digital-ocean.
Add a recipe for NodeJS.