[FIX] Website snippet - Update carousel to use bootstrap position and size without CSS. Fix bug with slide-to which doesn't work.
[TEST]for test on runbot.
[FIX] wesbite: banner - remove css and use bootstrap for positionning. Now hidden-xs works, we don't lost 50% of width
[FIX] Website_mail - Add selectors to allow drag and drop of snippet in email template
[MERGE][FIX] Mobile preview of blogs
[FIX] calendar: fix string quoting mess in email template