integration with rewrite programming

[kris-brown]

Some processes may require complicated sequences of events to take place, which could in principle be orchestrated with a ton of timers and dirac deltas and injection of implementation details into the world state ... but perhaps should be explicitly expressed as programs of a sort. Rather than Julia programs, though, we can use the graphical languages for schedules in AlgebraicRewriting. An example where this may be especially important is having support for declaring model initialization procedures.

One means this could be integrated is generalizing ABMRule to take a stochastic timer and a whole schedule, of which the schedule which contains just a single rewrite rule is a special case.