NEW: Activation checks for duplicate fieldnames, and refuses to attempt activation if they are found. Offers to fix problem, and if chosen renumbers the question, as well as the associated conditions, question_attributes and answers.

git-svn-id: file:///Users/Shitiz/Downloads/lssvn/trunk/unstable@1195 b72ed6b6-b9f8-46b5-92b4-906544132732