Back to work, some clean and fix

Add the possibility to correctly switch CPU/GPU on hello_world /
hello_world2 / convolution / reduce / scan / qjulia / mandelbulb

Add the possibility pass other parameter to the index.html like for
reduce sample you can call : index.html?mode=gpu&sample=6&param=float2
 (reduce work with : int / int2 / int4 / float / float2 / float4)
  if there many param you can use ',' for separate param like
&param=--device,GPU,--platform,0 it's similar to call the program :
./out gpu --device GPU --paltform 0

Inside the opencl_library now, if you want use GPU, but if you don't
have the device, you have a warning print in the console and in the
output. I use the default device in this case

Finished Mandelbulb now is work perfect on CPU / GPU with all the 3D
Rendering (Add qjulia image with transparency)

QJulia for work on CPU, is not perfect on Firefox i still have some
weird behavior, but i fix the ndRangeKernel problem