- Update jquery.recurrenceinput.js:
  - Fix ie8 startdate and fire events when changing checkbox values [deiferni],
  - Make "repeat forever" button optional [deiferni],
  - When there is no recurrence rule, the edit button should show "Add...", not
    "Edit..." [thet],
  - Remove ambiguous recurrence rule checkbox, which lead to UX confusion due
    to double negation (unchecked checkbox said "no recurrence rule") and add
    instead a "Delete" button. [thet]
fix i18n key error, delete button not doing event.preventDefault