Fix typo in Sign in with Titter link
Add twitter login icon.
Merge branch 'C1_mennaamr_#91_Facebook_login' of github.com:DevYah/coolsoft-13 into C1_mnzaki_#74_twitter_login

Conflicts:
	Idearator/app/views/layouts/_navigation.html.erb
Add missing twitter_screen_name_clash view
Merge branch 'master' of github.com:DevYah/coolsoft-13 into C1_mnzaki_#74_twitter_login

Conflicts:
	Idearator/Gemfile
	Idearator/Gemfile.lock
	Idearator/app/assets/javascripts/application.js
	Idearator/app/assets/stylesheets/user.css.scss
	Idearator/app/controllers/application_controller.rb
	Idearator/app/controllers/home_controller.rb
	Idearator/app/controllers/registrations_controller.rb
	Idearator/app/controllers/sessions_controller.rb
	Idearator/app/controllers/users_controller.rb
	Idearator/app/models/user.rb
	Idearator/app/views/devise/registrations/edit.html.erb
	Idearator/app/views/home/index.html.erb
	Idearator/app/views/layouts/_navigation.html.erb
	Idearator/config/environment.rb
	Idearator/config/routes.rb
	Idearator/spec/spec_helper.rb
Merge branch with Twitter Login