Fixed timing and added parallel CPU comparison
* Added concurrency::parallel_radixsort from Parallel Pattern Library (PPL)
  for better CPU comparison
* Fixed timing of GPU sort. Call to GPU code doesn't block, so you
  have to make it block before ending the timer.
* Changed the GPU input array from array_view to array to allow for
  separate compuation and data transfer timing. See
  blogs.msdn.com/b/nativeconcurrency/archive/2011/12/28/how-to-measure-the-performance-of-c-amp-algorithms.aspx
* Changed cout commands to printf (personal preference)
* Made each type of sort use exactly the same input data
* Note: CPU Sorting is *drastically* faster in Release mode. CPU parallel
  sort smokes the GPU version suprisingly.