A single-threaded nondeterministic feedback for TERTS.
Add a nondeterministic feedback for TERTS.
better comments
Improve comments. Reorder some statements for slightly better
performance.
Merge pull request #52 from gijsbers/master

This implements Distributed S-Net for the Front runtime system.
Merge pull request #53 from gijsbers/ndfb

Non-deterministic Feedback Combinator (thanks!)