Design API: refactoring, new KibaOneAccents class

[ Feature description ]

KibaOneAccent is a static class with which provides helper methods
to get accents information.

• KibaOneAccents::WHITE
  
  The color to use as white

• KibaOneAccents::BLACK
  
  The color to use as black

• KibaOneAccents::getAccents()
  
  Returns an array of all available accents.
  
  Each item is an array of 3 values:
  • the accent name
  • the accent color
  • the headings color (appliable for footer headings)

• KibaOneAccents::exists ($accentName)
  
  Determines if an accent exists

• KibaOneAccents::getAccentColor ($accentName)
  
  Gets the accent color of the specified accent

• KibaOneAccents::getHeadingColor ($accentName)
  
  Gets the headings color of the specified accent

[ Public API code change ]

The API code nows use the KibaOneAccents::getAccents() method.

[ Goal ]

To allow the use by our header/footer API of the accents information.