Expose CSRF Token refresh as a function

Refreshing CSRF tokens ensures that forms do not contain cached tokens.
This is currently done once, when jquery-ujs is loaded. If a cached form
is later loaded onto the page (say via a remote form for 'load more'),
the CSRF token is not udated.

This change exposes the CSRF token refreshing code at
`$.rails.refreshCSRFTokens` so it can be called at will without developers
having to re-implement the function.
Merge pull request #350 from derekprior/dp-refresh-csrf

Expose CSRF Token refresh as a function
Reorganize test suite custom CSS

The versions and CDN links won't be totally mangled by the QUnit
header now.
Added jquery 1.11.0 support. Removed jquery 1.7.x support.
Added older jquery 1.10.2 support.
Update the jQuery supported versions