Fix hidden and default calendars

They were not working. I had to remove some code from CodeIgniter input
validation that complained about keys containing dots or slashes.
Show event start and end dates formatted by moment.js

We can finally remove the old and ugly code that changed system timezone
to format dates with strftime!
Fix some visualization and editing issues with all day events

Fullcalendar 2.0 expects the end date to be exclusive on all day events. This
was causing some issues when showing the event details on both the popup and
the edit form.
Remove formatted_description, use description instead

Dust.js keeps line breaks, so there is no need to convert them to <br> tags