JP2OpenJPEG: deal correctly with datasets that have a color table

git-svn-id: https://svn.osgeo.org/gdal/trunk@27259 f0d54148-0727-0410-94bb-9a71ac55c965
NITF: deal correctly with JPEG2000 NITF datasets that have a color table inboth Image Subheader and JP2 boxes, and for drivers that don't do color table expension

git-svn-id: https://svn.osgeo.org/gdal/trunk@27260 f0d54148-0727-0410-94bb-9a71ac55c965
Merge branch 'trunk' into trunk_mingw