Hold erubis fo rmore test
Added new feature: post a public survey open to every registered users.

Added column to Survey table db/migrate/20130527153115_add_column_public.rb
Updated seeded file accordingly db/seeds.rb
Added the "open" conditions to the differents routes data searches:
app/controllers/index.rb
app/controllers/share.rb
app/controllers/survey_display.rb

Updated the view to add the public check box app/views/survey.erb
Added design for public button. Made it consistent with the create page
Changes done in public/css/create.css and app/views/survey.erb
Correct % bug
Correct % bug in display