added cpu vs gpu test to see if one convolution cpu based or gpu based gives identical results (was able to confirm that), deconvolution still is different (cpu based compared to gpu based)
* added ../tests/test_gpu_deconvolve_single_stepped.cu to test the individual steps of the gpu deconvolution for mismatches to the cpu equivalents
* moved cuda_kernels.cuh to inc (where it should be)
* due to the compilation of test_gpu_deconvolve_single_stepped.cu with nvcc a couple of errors in the cpu code occurred
** std::isinf and std::isnan is reject by nvcc 5.5.22 with an unknown identifier error (I removed std:: and added using std::isinf)
** warning that chunk_size is never referenced in cpu_kernels (this has to do with openmp pragmas being ignored)
started to add single stepped test cases to compare cpu and gpu deconvolution