First implementation of working CUDA code. Inefficient and risky.
Changed how cuda program accesses the Fortran modules.
Moved some code from GPU to CPU in four_strucf_cuda. Now runs faster.
Changed to passing complex cex and tcsf instead of separate real and imaginary componets. Using cuFloatComplex on CUDA side.
Fixed atom indexing in C program.
Cleanup and comments
Added support for CUDA 3D calculaion in four_strucf.
Fixed discus CMakeLists to allow merge into master.
Merge branch 'cuda'

Conflicts:
	discus/prog/CMakeLists.txt