GovMetric responsive snippet implementation

GovMetric have updated the snippet to replicate my existing changes
i.e. the use of image sprites to render the smiley images. This means
there is no need to host a modified script or CSS anymore.
Referencing GovMetric’s CDN due to the following:
When a smiley is clicked our functionality will pull down the required
JavaScript and CSS files (via the CDN) in order to display the modal
window which frames your survey.