Add support for generation of PLT markers in encoder

* -PLT switch added to opj_compress
* Add a opj_encoder_set_extra_options() function that
  accepts a PLT=YES option, and could be expanded later
  for other uses.

-------

Testing with a Sentinel2 10m band, T36JTT_20160914T074612_B02.jp2,
coming from S2A_MSIL1C_20160914T074612_N0204_R135_T36JTT_20160914T081456.SAFE

Decompress it to TIFF:
```
opj_uncompress -i T36JTT_20160914T074612_B02.jp2 -o T36JTT_20160914T074612_B02.tif
```

Recompress it with similar parameters as original:
```
opj_compress -n 5 -c [256,256],[256,256],[256,256],[256,256],[256,256] -t 1024,1024 -PLT -i T36JTT_20160914T074612_B02.tif -o T36JTT_20160914T074612_B02_PLT.jp2
```

Dump codestream detail with GDAL dump_jp2.py utility (https://github.com/OSGeo/gdal/blob/master/gdal/swig/python/samples/dump_jp2.py)
```
python dump_jp2.py T36JTT_20160914T074612_B02.jp2 > /tmp/dump_sentinel2_ori.txt
python dump_jp2.py T36JTT_20160914T074612_B02_PLT.jp2 > /tmp/dump_sentinel2_openjpeg_plt.txt
```

The diff between both show very similar structure, and identical number of packets in PLT markers

Now testing with Kakadu (KDU803_Demo_Apps_for_Linux-x86-64_200210)

Full file decompression:
```
kdu_expand -i T36JTT_20160914T074612_B02_PLT.jp2 -o tmp.tif

Consumed 121 tile-part(s) from a total of 121 tile(s).
Consumed 80,318,806 codestream bytes (excluding any file format) = 5.329697
bits/pel.
Processed using the multi-threaded environment, with
    8 parallel threads of execution
```

Partial decompresson (presumably using PLT markers):
```
kdu_expand -i T36JTT_20160914T074612_B02.jp2 -o tmp.pgm -region "{0.5,0.5},{0.01,0.01}"
kdu_expand -i T36JTT_20160914T074612_B02_PLT.jp2 -o tmp2.pgm  -region "{0.5,0.5},{0.01,0.01}"
diff tmp.pgm tmp2.pgm && echo "same !"
```

-------

Funded by ESA for S2-MPC project

1 files changed, 31 insertions, 0 deletions

diff --git a/src/lib/openjp2/openjpeg.c b/src/lib/openjp2/openjpeg.c
index e406cb49..1e2d60a6 100644
--- a/src/lib/openjp2/openjpeg.c
+++ b/src/lib/openjp2/openjpeg.c
@@ -652,6 +652,11 @@ opj_codec_t* OPJ_CALLCONV opj_create_compress(OPJ_CODEC_FORMAT p_format)
                 struct opj_image *,
                 struct opj_event_mgr *)) opj_j2k_setup_encoder;
 
+        l_codec->m_codec_data.m_compression.opj_encoder_set_extra_options = (OPJ_BOOL(
+                    *)(void *,
+                       const char* const*,
+                       struct opj_event_mgr *)) opj_j2k_encoder_set_extra_options;
+
         l_codec->m_codec = opj_j2k_create_compress();
         if (! l_codec->m_codec) {
             opj_free(l_codec);
@@ -690,6 +695,11 @@ opj_codec_t* OPJ_CALLCONV opj_create_compress(OPJ_CODEC_FORMAT p_format)
                 struct opj_image *,
                 struct opj_event_mgr *)) opj_jp2_setup_encoder;
 
+        l_codec->m_codec_data.m_compression.opj_encoder_set_extra_options = (OPJ_BOOL(
+                    *)(void *,
+                       const char* const*,
+                       struct opj_event_mgr *)) opj_jp2_encoder_set_extra_options;
+
         l_codec->m_codec = opj_jp2_create(OPJ_FALSE);
         if (! l_codec->m_codec) {
             opj_free(l_codec);
@@ -788,6 +798,27 @@ OPJ_BOOL OPJ_CALLCONV opj_setup_encoder(opj_codec_t *p_codec,
     return OPJ_FALSE;
 }
 
+/* ----------------------------------------------------------------------- */
+
+OPJ_BOOL OPJ_CALLCONV opj_encoder_set_extra_options(opj_codec_t *p_codec,
+        const char* const* options)
+{
+    if (p_codec) {
+        opj_codec_private_t * l_codec = (opj_codec_private_t *) p_codec;
+
+        if (! l_codec->is_decompressor) {
+            return l_codec->m_codec_data.m_compression.opj_encoder_set_extra_options(
+                       l_codec->m_codec,
+                       options,
+                       &(l_codec->m_event_mgr));
+        }
+    }
+
+    return OPJ_FALSE;
+}
+
+/* ----------------------------------------------------------------------- */
+
 OPJ_BOOL OPJ_CALLCONV opj_start_compress(opj_codec_t *p_codec,
         opj_image_t * p_image,
         opj_stream_t *p_stream)