Merge branch 'melinath'

* melinath:
  Revert "Made referencing containers optional on pages. Fixes a bug."
  Pre-merge cleanup.
  Fixed collapse classes
  Added contentlet unicode and fixed container context bug.
  Made referencing containers optional on pages. Fixes a bug.
  Added File unicode.
  Last random entry before more organized approach. Added documentation/admin display information and membersof templatetag. Fixed minor admin/template bugs.
  Reopened treechanges. Moved validation language to validators.py. Abstracted NodeForm to TreeForm.
  Added admin form validation to prevent: 1. a treemodel being its own parent (uses a validate_parents method added to the model.) 2. a node having the same path (i.e. parent+slug) as another Also added a ModelAdmin for the File model.
  Went back and fixed spacing issues with last cleanup. Also added some list display options to the redirect, template and page models to improve the admin site.
  Last random entry before more organized approach. Added documentation/admin display information and membersof templatetag. Fixed minor admin/template bugs.
  Reopened treechanges. Moved validation language to validators.py. Abstracted NodeForm to TreeForm.
  Added admin form validation to prevent: 1. a treemodel being its own parent (uses a validate_parents method added to the model.) 2. a node having the same path (i.e. parent+slug) as another Also added a ModelAdmin for the File model.
  Went back and fixed spacing issues with last cleanup. Also added some list display options to the redirect, template and page models to improve the admin site.