Adds display content model to manage the stories we can link to in the display position on the index page
adds migration file for the WildfireDisplayContent model
adds management of wildfire display content model to admin. removes hard-coded references in the view and adds queryset for the wildfire display content
implements random return of display content in view and displays on index page
Merge pull request #165 from SCPR/develop

Implements display content model...