Adding no-content message for search and empty feed. Closes #212.
Merge branch 'master' into no-content

Conflicts:
	templates/default/pages/home.tpl.php
Fixed delete file issue in Cherwell theme in MongoDB
Removing conflicting onboarding templates
More extensive initial plugins
Moving from Mongo to MongoClient

Fixes #352 - thanks!
Making the media uploader explicitly an audio-only plugin.
Some open graph tags
Minor host fix for multi tenancy
Extra period
Improved search action
Fixing double template loading issue
Homescreen icons
Unifying open graph headers
Corrected registration form in mobile view
URL sanitization
Host filter
Further host filtering
Background fix for Cherwell theme
Fixed host theme / plugin selection