- correct previous commit (for scalar gf, the new check was not compiling)
- correct windowing of linear mesh (left point corrected as right point for rounding error
- lazy_fourier and co --> fourier
- ex fourier --> make_gf_from_fourier to make a new gf
- = fourier (g) works only iif lhs is a view, like scalar.
- updated python (commented fourier method).