Added UIAlerts for failed Parse saves
Consistency in method-spacing
Gray transparent background color for buttons

It doesn’t look great, but it’s something that makes buttons more
explicitly button-y for now, and can be used as a backup.
Changed comment

I tried removing the button styling in login and signup, but then it
reverted to the Parse option, not the appDelegate specifications. We’ll
have to see how much we care about appearance consistency.