- 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
-> code was previously assuming mesh with only positive, fermionic matsubara freqs
-> changed wn_min to n_min (was misleading, since it was an index, not a frequency) / same for <-> max
-> changed doc accordingly
- added test for a 'real-life' GF + corresponding output
- added basic usage documentation for tail fitting from c++. Full implementation details yet to be written
