Distinction between OpenCL for CPU, GPU and Accelerators

configure --enable-opencl now only acitvates cpu ocl kernels.
--enable-opencl_gpu adds gpu support and --enable-opencl_acc adds
accelerator support.
The corresponding defines are HONEI_OPENCL, HONEI_OPENCL_GPU and
HONEI_OPENCL_ACC.

Signed-off-by: Dirk Ribbrock <dirk.ribbrock@math.uni-dortmund.de>
Advanced lbm ocl ops to Accelerator support

Signed-off-by: Dirk Ribbrock <dirk.ribbrock@math.uni-dortmund.de>