Feature request: Admin interface - being able to save before publishing

[okaysoraya]

I wanted to ask for a new feature for the admin interface.

Use case: Formatting a new piece (e.g. article or lesson plan) but not yet feeling it's ready to be published. I would love to be able to save it within the editor and preview it, before formally hitting Publish.

[esoterik]

This is a bug for previews on brand new lessons! the broken code is likely to be in https://github.com/EFForg/active_preview , not the SEC code base