ensure do not attempt to attach poll to new discussion in PostController_DiscussionFormOptions
make insert/delete operations transactional in model with try/catch using BeginTransaction/CommitTransaction/RollbackTransaction
make all ids in Polls/Questions/Options/Answers NOT NULL in Structure() except NULL options from user answers
Prevent partial answered question from beign saved. Stash errors for display on form and Inform message
Merge pull request #2 from x00/dev

Looks great.