Event countdown

[Pivotal Tracker](https://www.pivotaltracker.com/story/show/67462870)

* Add animations for page loading
* Events still exist 15 minutes after it has started on the site
* Converted many assets to use HTTPS security
* Refactored javascript file structure
* Refactored `Event#current_occurrences` to `Event#next_occurrences'
* Refactored `Event.next_occurrences` to `Event.next_event_occurrences'