Update example page - stamps without gradients, no proxy

This changes were present in gh-pages branch, but not in master.
When it comes to proxy -  S3 bucket has appropriate CORS settings.
Fix custom group scaling behavior

[#79176042]

Save action, triggered by history, was breaking it.
Fabric removes and restores group selection in .toJSON method, but
it doesn't fire all the events that we expect. So remove and restore
group selection manually, making sure that all the required events
are dispatched.
Release version 1.2.2

- group scaling fixed