Remove proxima nova and site verification

This wasn't working anyway due to a 403 on typekit's end. Custom fonts
are unnecessary; let's just use Helvetica Neue.

The site verification was included by the theme erroneously.

Change-Id: I6b48ade05b36d63ac6f7664f0dc3bcbc8834e82a
Reviewed-on: https://gerrit.causes.com/23120
Reviewed-by: Aiden Scandella <aiden@causes.com>
Tested-by: jenkins <jenkins@causes.com>