Improved date management for events.
changed the 'expired' event method to expire immediately when the time is past the end_time
changed the from/to methods which are used for validation to use the new start_date and end_date methods, instead of both using the event_date.
This fixes the bug of not validating events starting before midnight and ending just after.
Added a test to verify that such events can be constructed.
also, removed one view spec test that would fail because the user wasn't logged in... this is covered by a cucumber test so it's redundant anyway.