1. Introduce acanonize(state), which returns a canonical state and a
   (bit-encoded) label wether the encoded state was itself canonical
2. Use this labelled canonical state as inital color of each
   state. Now:
   - every redundant cycle has the same color (except for the label)
   - of each set of redundant cycles exactly one has the label set
3. Use the extended label to gather loop statistics.

A bool is passed to the worker function to store wether any work has
been done in an iterState round. To prevent cache line bouncing, each
worker thread has its own cache line aligned bool which is ultimately
merged.