Issue #31 Hide edit my event when not owner

Hide the event my event button in the event card view when the person viewing the event
is not its owner.
Issue #31 Remove username field from event form

Save username directly on event, no need to show it on the form.
Issue #31 User username to track upvotes

Use username instead of email address to track if a user has upvoted or not.
Issue #31 Only owners see edit form

Only owners of events can see the event form when trying to edit them.
Introduce a view that shows a message saying that you are not the user and cannot edit this.
Issue #31 Don't authorize on no username

When event has no username don't attempt to authorize based on it
Issue #31 Styling so that sidebar is below event

Remove enforced heights from event image and info so that the event info
can be seen clearly below the image in smaller displays.
Issue #31 Styling to fit event page in center

Give sidebar and event page max widths. Center sidebar and event page content.
Issue #31 Prettify event card header a bit

Add a request handler for getting full country name.
Show full country name on event in the template.
Add a template helper to show the full date time in a prettier way.
Issue #31 Prettify navbar collapse

Rework navbar dom so that collapsing the navbar cleans up all links.
Login info still appears out of place when navbar opens.
Issue #31 Rework navbar dom to handle user buttons

User buttons now fit squarely in collapsing navbar.
Issue #31 More dom cleanup for register buttons

Cleanup dom in navbar for register and login buttons.
Issue #23 Change paperclip cropping to minimum

Now image will be resized to medium level even if the cut out section is smaller
than the resize dimensions.