prepare OpenCL kernels support, try to adapt blake.cl

Not finished! (committed to test/debug on windows)

Sample usage :

ccminer -a blake -o stratum+tcp://www.hashharder.com:9585 -i 18 \
 -u NaEcVrdzoCWHUYXb7X8QoafoKS9UV69Yk4 -p x -k blake256.cl -K /work/bitcoin/ccminer/opencl
blake2s cpu algo for future use

blake2sp could be a better idea for future gpu port