Complete reorganization of the Predis\Connection namespace.

* Renamed SingleConnectionInterface to NodeConnectionInterface since
  this name is better and makes even more sense in the context of
  cluster and replication scenarios.

* Moved specialized aggregate connections (the ones implementing both
  predis and redis cluster and master/slave replication) in a newly
  created Predis\Connection\Aggregate sub-namespace.

* Removed the "Connection" part from names of aggregate connection
  interfaces in the Predis\Connection\Aggregate sub-namespace.

* Changed "Composable" to "Composite" in the name of interfaces and
  classes that can use pluggable protocol processors.
Rename ComposableProtocolProcessor to CompositeProtocolProcessor.
Merge branch 'v1.0.0-dev/connection-namespace'
Fix parsing of the output of CLUSTER NODES to fetch slots map.

There was an error in presence of slaves in the cluster configuration,
see #165 for reference.