Fuzzy properties for pipes

These new pipe rules are fuzzy, insofar as they report partial success upwards immediately.
As theory and partial success is now the same thing, the need for gen-links to propagate hypotheses upwards has been eliminated, classic bachian link structure is enough.

There is a way to encode alternatives: a branch in the por/ret path, with no sur/sub upwards links from the nodes in the branch.

I have a growing suspicion that forcing alternatives into sub/sur or por/ret is a bad idea, though. Alternatives require abstraction, so cat/exp is going to play a role.