remove notification cout from load sidebar
remove activity feeds
refactor navbar preference: add new navbar preference table
add course notification controller
javascript for async load of notifications
add gem: better_errors for development
add gem: simple form, for form rendering
add gem: cocoon, dynamic nested form
add gem: haml, better markup
refactoring, move populate original url to application.js
sidebar refactor: controller and view
bring back activities
Merge branch 'dev/refactoring_sidebar' of github.com:Coursemology/coursemology.org into dev/raymoond_dev

Conflicts:
	Gemfile
	db/schema.rb