Sander Wahls

This would make calling mex files more efficient as the conversion to the complex array layout where real and imaginary parts are separated could be skipped. https://nl.mathworks.com/help/matlab/matlab_external/matlab-support-for-interleaved-complex.html https://nl.mathworks.com/help/matlab/matlab_external/upgrade-mex-files-to-use-interleaved-complex.html

Make changing FNFT_REAL to single and quad precision types work. Update tests where necessary.