This version of the StyleGrid has the second scent of Cocoa build support in it. Note that Cocoa build support is in no way supposed to be usable or complete yet.

New in b1:
   * Scrollbars now work and are correctly drawn.
   * Focus handling now works and is correctly drawn.
   * Changed text rendering to CoreText.
   * Fixed a crash when using the mouse wheel.

Known Cocoa issues:
   * Italic style when using System font will not work. (This is likely to not be resolvable in Cocoa)
