coalesce cells
add cr's only where needed

skip unquote-quote markdowns (maybe overzealous though)
crunch markdown quotes more carefully and thoroughly
put cell in edit mode when coalesced

also improve comments
Merge branch 'develop' into feature/coalesce-split

Conflicts:
	htdocs/js/rcloud_bundle.min.js
split cell

closes #271
Merge branch 'feature/coalesce-split' into develop