Re-enabled SEI message processing. (#79)

* * rocDecode/HEVC: Re-enabled SEI message processing.
  - Added "-sei" command option to extract SEI messages from stream.
  - Added support for SEI info parsing for multiple SEI NAL units with multiple payloads.
  - Fixed a SEI syntax parsing issue and several procssing issues.
  - Fixed a double free memory issue in SEI data buffer handling in HandlePictureDisplay().

* * rocDecode/HEVC: Coding format changes.

* * rocDecode/HEVC: Minor format changes.

utils/rocvideodecode/roc_video_dec.cpp

@@ -465,7 +465,9 @@ int RocVideoDecoder::HandlePictureDisplay(RocdecParserDispInfo *pDispInfo) {
                 }
             }
             free(sei_message_display_q_[pDispInfo->picture_index].pSEIData);
+            sei_message_display_q_[pDispInfo->picture_index].pSEIData = NULL; // to avoid double free
             free(sei_message_display_q_[pDispInfo->picture_index].pSEIMessage);
+            sei_message_display_q_[pDispInfo->picture_index].pSEIMessage = NULL; // to avoid double free
         }
     }