Original commit message from CVS:
* ext/libpng/Makefile.am:
* ext/libpng/gstpng.c: (plugin_init):
* ext/libpng/gstpngdec.c: (user_error_fn), (user_warning_fn),
(gst_pngdec_get_type), (gst_pngdec_base_init),
(gst_pngdec_class_init), (gst_pngdec_sinklink), (gst_pngdec_init),
(gst_pngdec_src_getcaps), (user_read_data), (gst_pngdec_chain):
* ext/libpng/gstpngdec.h:
Added png decoder.