Fixes for OpenCL global variables to be in __constant address space

1. nbnxn_consts.h contains constants shared between the OpenCL device
code and the host code. Added a macro CONSTANT_ADDRESS_SPACE which is
__constant for the devce, const for host. Name can be improved
2. Moved #define __IN_OPENCL_KERNEL__ from nbnxn_ocl_kernel_utils.clh to
nbnxn_ocl_kernels.cl
pmalloc, cl_float3, aux kernels fixes from dk-dev
Merge pull request #23 from StreamComputing/dk

Dk
Fixes for OCL include paths when running from VS
Removed nbfp, nbfp_comb from host and device code

The two buffers are not used.
They were used in the CUDA code as buffers to which to bind the
textures. This is not needed in OpenCL.