Uses OpenCL to run the mandelbrot function on GPU.

While it does run real-time on an already old graphics card 
(ATI Mobility Radeon HD4650) with an FPS ranging from 5-30
(depending on the iterations), it can be hugely increased
if the below tricks are used;

*** use floats to write to output array to ensure coalescence
   in older or demanding GPUs that only deal with consecutive bytes
*** don't transfer back the results, use CL/GL interop to switch
   buffers on the GPU