Merge pull request #1022 from rouault/partial_component_decoding

Add capability to decode only a subset of all components of an image.

diff --cc src/bin/jp2/opj_decompress.c
Simple merge

diff --cc src/lib/openjp2/j2k.c
Simple merge

diff --cc src/lib/openjp2/j2k.h
Simple merge

diff --cc src/lib/openjp2/jp2.c
Simple merge