Fix all-day database entries with seconds

[HALtheWise]

According to #201 , it should no longer be possible to create an all-day event starting or ending any time except midnight. If any of those currently exist in the database, we should fix them.

[osteele]

There's 36 of these in production db.getCollection('event').find({$where : function() { return this.allDay && this.end.getSeconds() != 0 }}). getMinutes() != 0 returns presumably the same 36; getHours() != 0 returns 35 because _id=5978bfa17412b80011ab821f "Students begin arriving after 12pm" ends a second shy of 1am EST.