Backend changes required for moving idea order on IdeaLinks, and having a root idea.  Frontend and moving all_posts calculations still TODO
Count posts for root
Merge branch 'develop' of https://github.com/ImaginationForPeople/assembl into root_idea_and_order_on_idea_link
RootIdea in changes
protect root idea
add rootidea to models
root attribute on root idea
rootidea type in app.js
special casing display of root idea