Added Win32 specific declspecs for making DLLs
Added tracing to S4r/Layer.cpp
Rename j0 to not conflict with builtin name.
Merge branch 'master' of https://github.com/victorliu/S4
Fixed GetFieldPlane bug with incorrect output when nu != nv due to
incorrect FFT striding.
Fixed const correctness on 2D sampler constructor.
Merge branch 'master' of github.com:victorliu/S4

Conflicts:
	modules/function_sampler_2d.c
	modules/function_sampler_2d.h