ext/jp2k/: Add image/x-jpc caps name for real, raw JPEG2000 codestream data.

ext/jp2k/: Add image/x-jpc caps name for real, raw JPEG2000 codestream data.

Original commit message from CVS:
* ext/jp2k/gstjasperdec.c: (gst_jasper_dec_sink_setcaps):
* ext/jp2k/gstjasperenc.c: (gst_jasper_enc_reset),
(gst_jasper_enc_set_src_caps), (gst_jasper_enc_init_encoder),
(gst_jasper_enc_sink_setcaps), (gst_jasper_enc_get_data):
* ext/jp2k/gstjasperenc.h:
Add image/x-jpc caps name for real, raw JPEG2000 codestream data.
In 0.11 we should merge image/x-j2c and image/x-jpc and simply drop
the non-standard boxing in the jasper elements and handle it in
qtmux/qtdemux.
image/x-jpc will be used by mxfdemux later.
Also add support for JP2 output in jp2kenc.