'orange' style should have color: 'black'
Handle defaut styles

 - Add 'badgee.defaultStyle()' method to get/set default style
   properties
 - `badgee.style(name)` now returns the properties of an existing named
   style
 - Add a few built-in styles : black, blue, brown, gray, cyan, magenta,
   pink
Version 1.1.0