README

This is an initial release and still requires documentation. I also want to make it easier for people to override the
methods for drawing the control elements so that developers can use it to create rotary controls of there own.

Know Issues
- Currently the minimumDomain and maximumDomain are not respected when the style is NDRotatorStyleLinear and wrapAround
  is YES.
- No unit tests.
- Added means to specify the the base or the thumb are rotated, so that a cached image can be used for all values by simple
  ration.
- Add a means to turn of caching for thumb or base if the look of the thumb or base changing to much for changes in value
  for caching to be useful. Perhaps a mechanism for post processing of cached images could be added to get the best of both
  worlds, no caching consume too many CPU cycles except for really basic images on low powers devices like iPhone.