Always append foundation to application stylesheet.

I removed the detection of require_self, since that might be gone
from an application that's written using Compass exclusively.
There is no need for the require to be appended immediately
after require_self, and this change makes the generator work
on more permutations of the application stylesheet.
Merge pull request #1865 from tilsammans/always-append-to-application-css

Always append foundation to application stylesheet.