message: vertexcodec: Fix TRACE=3 output
  rawbuffer contained vertices that were offset by 1, making deltas
  non-sensical.
diff: @@ -523,11 +523,12 @@ static unsigned char* encodeVertexBlock(unsigned char* data, const unsigned char
  unsigned char delta = zigzag8(vertex_data[vertex_offset] - p);
  buffer[i] = delta;
  - vertex_offset += vertex_size;
  #if TRACE > 2
  rawbuffer[i] = vertex_data[vertex_offset];
  #endif
  +
  + vertex_offset += vertex_size;
  }
  #if TRACE > 0
  @@ -548,7 +549,7 @@ static unsigned char* encodeVertexBlock(unsigned char* data, const unsigned char
  for (size_t i = 0; i < vertex_count; ++i)
  {
  stats.bitsopt[k] += bits(buffer[i]);
  - stats.bitsenc[k] += bits(buffer[i]) + bits(bits(buffer[i]));
  + stats.bitsenc[k] += bits(buffer[i]) + bits(char(bits(buffer[i])));
  }
  stats.headers[k] += stats.current_headers;
  