OCL: ocl::context now stores a vector of smart pointers
OCL: ocl::program now stores a vector of smart pointers
Linalg/OpenCL : Fixed a couple of warnings in GEMM
Linalg/OpenCL : Cleaned some dead code
Linalg/OpenCL : Normalized the arguments names, more blas-like. x,y,z for vectors ; A,B,C for matrices