Allow undo/redo for Markdown edits via buttons

[tedw]

Add ability to undo/redo Markdown edits made by clicking the toolbar buttons

Possibly add undo/redo buttons to toolbar as well

[tedw]

What do you all think about using https://trix-editor.org for the Markdown editor? It already has this functionality.

[defbyte]

but is says it:

outputs terse and consistent HTML.

does it support Markdown authoring?

[tedw]

Ah, good point, will investigate.