[JRO] Update CanCan and Rake
[JRO] What is this crap?

Deleting.
[JRO] Refactor abilities and clean up

* Refactor abilities and extract things out to service objects related to permissions
* Use CanCan in as many places as possible instead of using long conditionals
* Change html links to `/` to use `link_to`
* Fix over-eager-loading. Memory spikes were killing the app
* Entire new posts are built with their parent 
* Rename `for_user` to `including_roles_for`. Better naming
* Update messageboard_spec. Double to single quotes
[JRO] Temporarily restore "edit".

Too many complaints without it.
[JRO] Call out Ruby 2.0 requirement in README
[JRO] Turn editing features back on

* Make sure admins can edit posts too.
* Add quiet_assets gem to Gemfile
* Fix private thread privacy