displayPeriod as a HyPerCol parameter made available to all objects

[peteschultz]

displayPeriod started out as a Movie parameter, and it is still only defined for Movie, MoviePvp, and Patterns (the last of which hasn't been used in quite a while). However, it is very common for objects to trigger off of these layers, with more than one possible triggering behavior, creating difficult-to-manage interdependencies.

Accordingly, I'm thinking that it would make sense to have displayPeriod be a HyPerCol parameter, and pass that parameter (or perhaps the time to next display period) as an argument to updateState. This would make the most common reason for triggering unnecessary.

Thoughts?

[austinthresher]

I like this idea a lot. The only potential issue I can think of is Gar's taps- they might not work with a setup like this.