Fixes bug when submiting container form

This bug happens when you submit container form on admin without
filling the slug or channel field.
Merge pull request #356 from mauler/bugfix-containerform

Fixes bug when submiting container form
added @campusparty Opps sponsor
Merge branch 'master' of github.com:opps/opps

* 'master' of github.com:opps/opps:
  Fixes bug when submiting container form
  Fixes opps base View init
  Fixes opps View class for class based views
  Revert "Adds OPPS_CHANNEL_LAYOUT configuration"
  Fixes typo
  Adds OPPS_CHANNEL_LAYOUT configuration