Fixes the problem with rectilinear fields.
This is done by introducing a new spacing system called "grid_spacing" which keeps the spacing for each dimension separately as a numpy array which indicates the location of each element in that dimension.
The absence of scan to siddon is not considered breaking anymore, as some files don't have it but are valid xdr files (at least from experience).
Fixes the problem with rectilinear fields. This is done by introducing a new spacing system called "grid_spacing" which keeps the spacing for each dimension separately as a numpy array which indicates the location of each element in that dimension. The absence of scan to siddon is not considered breaking anymore, as some files don't have it but are valid xdr files (at least from experience).