Add bytes dependency

Instead of using Vec<u8>, the Mini-Redis crate uses Bytes from the bytes crate. The goal of Bytes is to provide a robust byte array structure for network programming. The biggest feature it adds over Vec<u8> is shallow cloning. In other words, calling clone() on a Bytes instance does not copy the underlying data. Instead, a Bytes instance is a reference-counted handle to some underlying data. The Bytes type is roughly an Arc<Vec<u8>> but with some added capabilities.

To depend on bytes, add the following to your Cargo.toml in the [dependencies] section:

bytes = "1"