Refactor empty section logic for multi-section table views
Refactor app to use AppSettings.h
Basic styling for most view controllers

Begins the styling process with the following:
  - Proper UITabBarItem colors for normal/selected states
  - Darkens the UINavigationBar to the dark blue of the top of the bg
    image
  - Sets the bg image for each view controller via a superclass
  - Sets the default UILabel text color to white for all UILabels
    inside a UITableViewCell
  - Proper header colors for Ballot & Details views
  - Styled about this app section
Update SocialMedia icons
Update candidate default blank image

Also deleted old placeholder social media/candidate default images
Add VIPColor class

This class contains all of the UI color definitions, as well as a way
to override the defaults by setting alt colors in settings.plist

Makes use of new UIColor+Hex category which generates UIColors from
hex strings.
Update existing UIColor code modifications with VIPColor

Also added method color:withAlpha to VIPColor
Revert all Storyboard styling to default

If we are going to allow for customization of the app style
via configuration settings, we need to do all our styling in code.