Allow for `1D` inputs

[LecrisUT]

Are there some complications why minimizing the spread for 1D or other dimensions is not implemented?

For now I am trying to fake the 1d system, but I am not sure if it's the appropriate way:

begin unit_cell_cart
Ang
   1.0     0.0      0.0
   0.0   100.0      0.0
   0.0     0.0    100.0
end unit_cell_cart
 
use_bloch_phases = .true.
 
num_bands    4
num_wann    4
 
write_u_matrices = .true.
write_xyz = .true.
 
mp_grid    10   1   1
 
begin kpoints
    0.0    0.0    0.0
   -0.1    0.0    0.0
    0.1    0.0    0.0
   -0.2    0.0    0.0
    0.2    0.0    0.0
   -0.3    0.0    0.0
    0.3    0.0    0.0
   -0.4    0.0    0.0
    0.4    0.0    0.0
   -0.5    0.0    0.0
end kpoints 

One thing that concerns me is that nnkp contains:

     1     1      0   1   0
     1     1      0   0   1
     1     1      0   0  -1
     1     1      0  -1   0