Also the :replicates info field in the node object is now correctly
populated. This also fixes the :replicas field computation.

Show options if any. Clarify that for some command any node address is
ok.

Later this should be configurable from the command line but at least now
we use something more appropriate for our use case compared to the
redis-rb default timeout.

The hope is that the new one is more readable.

This is needed in order to colorize it as next step.
We use conventions in output messages such as

>>> This is an action
*** This is a warning
[ERR] This is an error
[OK] That's fine

And so forth, so that a color will be associated checking the first
three chars.

Slot zero was hardcoded (!)

Open slots are slots found in importing or migrating slot when a
cluster check is performed.