Introduce Byte{Reader,Writer}.{Read,Write}Enum

[mibac138]

This makes the code clearer, it's more convenient than casting to number-types, and is smaller on the wire (as some enums were needlessly sent as an int).

[notfood]

Looks nice. My only concern is how it affects performance. There may be places you don't want to repeatedly call Enum.GetValues. I suspect ScheduledCommand gets called a lot and it may not need that abstraction.

[mibac138]

That's a fair point. I've introduce a cache to only call Enum.GetValues once and went back to using {Read,Write}Byte directly in ScheduledCommand