Add skeletal responsive css files

Use of these files is controlled by a config param or, on individual
requests, by a request param.
Add foundation-rails gem
Add foundation to the sass load paths

Necessary because we're importing it from a subdirectory
Include normalize.scss from foundation

To reset browser differences.
First attempt at responsive header.
Add styling for popups
Add frontpage styling
Order page elements consistently with other pages.

'right_column' appears after content it will be to the right hand side
of on other pages. It doesn't matter to the current stylesheet, which
floats it anyway, but is easier to handle in responsive css if the
markup is consistent.
Remove the quote from a comment in request correspondence.

It gets hidden by the current stylesheet, so easier and more efficient
not to render it at all.
WIP