Anonymous gist creation will be removed - #6232
Instead of publishing gists, when we share we now encode the code into
the URL fragment, in compressed Base64 encoded form. (see code comments
for the exact format)
Existing gists still load as before.
1. Replace all usage of CesiumViewerWidget with the new Viewer widget.
2. Delete `Client CZML` example becasue it's no longer needed and redundant with `Simple CZML Demo`
3. Delete `Two Viewer Widgets` because we aren't ready to support multiple scenes the correct way. The technique used by this demo resulted in poor performance and lots of data duplication.
Scott Hunter
Matthew Amato
andre-nunes