Add ShowDoubleFloatArrays.transposeJagged(double[][][], int n_comp, int n_inner)
which converts the common [outer][inner][comp] layout (with null outer or inner
entries) to [outer][comp][inner] substituting NaN for nulls.  This pattern
appeared inline in getNadirDisparityMaps() and recurs in other tile-processing
code.

Refactor getNadirDisparityMaps() to replace the 12-line inline transpose loop
with a single call to the new utility, keeping the same semantics.
Co-authored-by: Claude <claude@elphel.com>