[#71535126] Remove images and headings from marked

Modify marked to remove images and headings from its parser.
Escape text being shown in comments.
Merge branch 'master' into custom_markdown

Conflicts:
	app/assets/javascripts/kiwi/components/comments/comments.js.coffee
[#71535126] Upgrade underscore, 1.6.0

Upgrade underscore to version 1.6.0
Merge pull request #140 from Forekasting/custom_markdown

Custom markdown
[#71702552] Refactor access to user in comments

Use request to get the current logged in user.
Store current user on views as metadata instead of on the collections
creating the events.
Introduce moderator role and add moderator role to abilities.
[#72390930] Only re render on deleter change

Stop re rerendering the whole comment on every change.
Add a spec to ensure that the comment switches to a deleted comment
after being deleted.
[#72390930] Reload replies to a deleted comment

After a comment is deleted, use dom:refresh to put its replies back into
the DOM.
Merge branch 'master' into moderator_delete

Conflicts:
	app/assets/javascripts/kiwi/components/comments/comments.js.coffee
	spec/javascripts/comment_spec.js.coffee
[#72390930] Rerender replies after comment delete

Switch to using dom refresh to show replies so that after delete replies
are rendered.