Recognize New Headers

pantheon-systems/pantheon-edge-integrations v0.3.0 was updated to support additional/new personalization headers that will be used moving forward for Edge Integrations sites. However, smart_content_cdn does not appear to recognize these headers. No geo changes work when the new headers are used only and the dropdown menu only shows a single Geo value, rather than multiple Geo values.

Original Request: https://github.com/pantheon-systems/smart_content_cdn/issues/25