Adding formatter should invalidate cache

[jcubic]

Issue summary

The cache is not invalidated when adding formatted and refreshing the view

Expected behavior

The cache should be invalidated and if the existing output is formatted.

Actual behavior

Formatter is ignored after refresh

Steps to reproduce

See emoji demo.
Remove clear_cache() call and refresh the page, 😃 is not rendered.

[jcubic]

The solution may be to clear the cache on refresh() also it's worth adding refresh of CMD to that funciton.