[fix bug 869141] Move google analytics code to another file.

Inline script execution is blocked from CSP rules. Moved the code to
another file which fixes the problem and results in cleaner HTML.
[fix bug 859973] Group listing improvements.

 - Count and sort only with vouched members in groups.
 - Simplified template rendering.
 - Clean 'sort' values with a proper Form()
Merge pull request #500 from glogiotatidis/ga-csp-fix

[fix bug 869141] Move google analytics code to another file.
[fix bug 873487] Upgrade django-browserid.

* Upgrade django-browserid and remove custom browserid code.
* New middleware RegistrationMiddleware to ensure that new mozillians
  complete registration before moving to other pages.
Merge pull request #505 from glogiotatidis/browse-groups

[fix bug 859973] Group listing improvements.
Merge pull request #501 from glogiotatidis/django-browserid-upgrade

[fix bug 873487] Upgrade django-browserid.
[Fix Bug 880016] Don't pass empty string to group sort
[Bug 879052] Adding new styles to profile detail page.