Use byte strings for digital reads/writes

[epage]

bytes strings seem to be the method focused on for parsing binary data in python. The struct and array modules help dissect bytes into smaller bits of useful information.

I found this out when working on the nixnet API where I needed to parse arrays of uint8_t's into frames. See https://github.com/ni/nixnet-python/blob/master/nixnet/_frames.py#L13

[epage]

I think this would be most valuable for port reads/writes. It might also be useful for line reads/writes but I also think the bool arrays are useful.