Move CLI helpers into package(s) to be part of API

[davemt]

There are a few helpers in the parsefile cli example that would be useful if made available as part of package(s) rather than just the cli program. For example, sync function, and functions to read PAT/PMT. I think they are general enough (with a couple of tweaks) that it could save from people needing to repeat those bits of code.

[guygrigsby]

I think that this makes sense. I'll take a look at it when I can. If anyone else is interested in this, go for it. Don't wait on me.