added description field to cfps

closes #1650

done some changes

minor changes

added markdown format to cfp#show

fixed description text  position in proposals

fixed truncated description text in show action

minor changes on non-admin side

app/views/admin/cfps/_booths_cfp.html.haml

@@ -11,6 +11,10 @@
 %dd
   = @cfp.end_date.strftime('%A, %B %e. %Y')
 %dt
-  Days Left:
+  Description
+%dd
+  = markdown(@cfp.description)
+%dt
+  Days Left
 %dd
   = pluralize(@cfp.remaining_days, 'day')