Only send subscription emails when subscribed is true
More efficient `subscribers` query
Merge branch 'email-subjects'
Reload current user when visiting /settings

Closes #131
Max height and scroll for broadcast groups list

Closes #119
Merge branch 'issue-131'

Conflicts:
	app/assets/javascripts/client-prod.js
HTML emails
Remove redundency in email
Sanitize HTML rendered from Markdown
`link_to` instead of manual <a> tags in HTML views
Grammar
User roles
Can ask if a user has multiple roles
Check required_roles against user in Ability#can?
Only show subforums that the user's roles permit
WIP: fix tests
Fix user role tests
Require roles to see threads
Pull subforum required roles query into method
Use a scope instead of a method