Add ability to preview (and edit) an email before sending from saved donation

The ability to generate emails (as well as letters) upon saving a donation is a nice new feature, but it would be significantly better if the email could be at least previewed and preferably edited before it is sent (similar to how letters are handled).

It is now harder to preview acknowledgement emails (you can't if they have already been sent previously - so you need a copy that is unsent to preview... which clutters up your inbox) and with different versions of acknowledgements for tributes, donor advised funds, soft credits, in-kind donations, and so forth (which have to be separate due to not having conditionals in emails) it gets easy for a volunteer to accidentally select the wrong email name before saving... and then it is too late.

A preview before the save would help. Ability to edit (to handle specific odd cases) would be WONDERFUL.