Monitor mode works with other data as well

@antirez in the spec you state the following:

> The connection can only be used for Pub/Sub or MONITOR once setup in this way

However, when being in MONITOR mode Redis will still respond with regular commands if send by the client being in MONITOR mode. The data is send in addition to the actual monitoring information. I actually have a implementation where I use a regular expression to distinguish regular data from the monitoring information (there is no other way AFAIK).

This should likely either be officially supported or the support for that should be removed. I was not sure if it's best to open here or directly for Redis. Please just move the issue if you feel it is best tracked elsewhere.