Restrict *_Fourier_wave_vector.seq_id data items to positive integers

[vaitkus]

This PR sets the enumeration range of _atom_site_Fourier_wave_vector.seq_id and linked data items to 1: (see COMCIFS/magnetic_dic#69 (comment) for the reasoning behind this). In several cases the default value was also changed from 0 to 1 to be compatible with the new enumeration range restrictions.

[vaitkus]

PR #30 homogenised the _Fourier_wave_vector.seq_id data items definitions by marking them all as Integers with the range of '0:'. The magCIF dictionary, however, still defines _atom_site_Fourier_wave_vector.seq_id with the enumeration range of '1:' following the recommendations of Gotzon (see COMCIFS/magnetic_dic#69 (comment)). Should the msCIF dictionary be updated accordingly or should magCIF dictionary now be updated?

Note, that in case this dictionary needs updating, I will create a new PR as that will take sufficiently less effort than updating this one.