Using the dynamic type here is no better than object because the values are
primitive types -- more likely to be cast/typechecked than used as a receiver
param for a method call.
MemApi.ReadByteRange now returns the requested number of bytes and not 1 extra,
MemApi.ReadByteRange now warns only once per call for addrs outside range,
MemApi.ReadByteRange now warns for negative addrs (once per call; previous
implementation passed negative addresses to PeekByte), MemApi.WriteByteRange now
warns only once per call for addrs outside range, MemApi.WriteByteRange now
warns for negative addrs (once per call; previous implementation passed negative
addresses to PokeByte)