vertexcodec: Implement summary traces
vertexcodec: Implement summary traces

You can now select the level of tracing: 0 for no tracing, 1 for tracing
stats about each column in each vertex block and 2 for tracing each
vertex.

Summary stats include max value and number of unique values for now.

zeux/meshoptimizer,zeux/meshoptimizer,zeux/meshoptimizer