Update composer.json.
Create the Predis\Response namespace.

All of the response interface, classes and exceptions have been moved
into this namespace.
Move the Predis\Iterator namespace into Predis\Response.
Update CHANGELOG.
Update CHANGELOG.
Merge branch 'v0.9/response-namespace'
[tests] Fix tests.
Rename classes in Predis\Response and Predis\Response\Iterator.

This change aims to make class names shorter with less redundant fully
qualified names.

Merge!
Update CHANGELOG.
Merge branch 'v0.9/rename-response-classes'
[tests] Remove useless backslash in "use" directive.
Rename session handler class.
Rename classes in the Predis\PubSub namespace.
Merge branch 'v0.9/rename-pubsubcontext'
Fix phpdocs.
Rename classes in Predis\Monitor namespace.
Merge branch 'v0.9/rename-monitorcontext'
Rename interfaces and classes in the Predis\Cluster namespace.

A few methods were renamed accordingly for consistency
Merge branch 'v0.9/rename-cluster-classes'
Rename classes in Predis\Transaction.