refs https://github.com/TryGhost/Ghost-Admin/pull/690, closes#1501, closes#2093, closes#4592, closes#4627, closes#4659, closes#5039, closes#5237, closes#5587, closes#5625, closes#5632, closes#5822, closes#5939, closes#6840, closes#7183, closes#7536
- replace custom showdown fork with markdown-it
- swaps showdown for markdown-it when rendering markdown
- match existing header ID behaviour
- allow headers without a space after the #s
- add duplicate header ID handling
- remove legacy markdown spec
- move markdown-it setup into markdown-converter util
- update mobiledoc specs to match markdown-it newline behaviour
- update data-generator HTML to match markdown-it newline behaviour
- fix Post "converts html to plaintext" test
- update rss spec to match markdown-it newline behaviour
- close almost all related showdown bugs
no issue
- change out should.equal for // jshint ignore:line
- ensure should is the first require in every test, and ALWAYS require
- make sinon the second require, and sandbox the last thing
- ALWAYS use sandbox, futureproofs tests against contributors who don't know it
- change require formatting
refs #7429
- ☢️👷🏻♀️ This PR removes the dependency on Ghost-Editor and replaces it with the Mobiledoc DOM renderer. It includes new DOM based default cards and atoms.
