unu crop: Crop along each axis to make a smaller nrrd
Usage: unu crop -min <pos0 ...> -max <pos0 ...> [-i <nin>] [-o <nout>]
-min <pos0 ...> = low corner of bounding box.
o <int> gives 0-based index
o M, M+<int>, M-<int> give index relative to the last
sample on the axis (M == #samples-1).
(1 or more positions)
-max <pos0 ...> = high corner of bounding box. Besides the specification
styles described above, there's also:
o m+<int> give index relative to minimum.
(1 or more positions)
-i <nin> = input nrrd
-o <nout> = output nrrd (string); default: "-"
