Add the calendar_date_select plugin as a submodule
Update to new syntax for adding a tab to admin UI
Strip trailing whitespaces
Fix r:events:in_range tag for ruby 1.9

In ruby 1.8
  Array.to_s is like Array.join

In ruby 1.9:
  Array.to_s is like Array.inspect
http://stackoverflow.com/a/3960429/128850
Only show calendar select if current page is an event