Added a utility to get the device info (number of threads)

./get-device-info.x prints all the platforms and all the devices.
For each device the name and the maximum number of compute units is printed.

	modified:   include/OpenCL_utils.h
	modified:   src/OpenCL_utils.c
	new file:   src/get-device-info.c
Merge branch 'master' of https://github.com/ajasja/ljmd-opencl