Includes the removal of all tabs and submit action buttons when 'Drafts' or 'Sent Items' are clicked and the addition of an 'add one' link on 'Drafts' folder page.
For more information see: http://www.elijahlofgren.com/silverstripe/newletter-tree-and-tab-row-are-confusing/
Includes a few fixes for undefined variables. (merged from branches/gsoc)
git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/cms/trunk@41772 467b73ca-7a2a-4603-9d3b-597d59a354a9
