[cmake-warning-fix][cmake-3.0-policy-CMP0043]

CMake 3.0 introduced policy CMP0043 which ignores the use of
COMPILE_DEFINITIONS_ suffixed variables, set policy behavior to OLD for
compatibility with version >3.0.
[cmake-warning-fix][cmake-3.0-policy-CMP0042]
Adding missing includes
Added FindOpenCL.cmake from https://gitorious.org/findopencl project
Added OpenCL support
Merge pull request #508 from tpaviot/review/cmake-policy-0043-fix

Fix CMake 3.0 warning about policy CMP0043
Merge pull request #511 from tpaviot/review/missing-include

Adding missing includes
Merge pull request #505 from tpaviot/review/opencl-support

Adding missing OpenCL support