Make flush() not care about redis cluster
Make train() and untrain() not care about redis cluster
Make _redis_script_load auto add namespace and labels
Make scores() not care about redis cluster
Make classify() not use scores() internally

The classify method now uses its own luascript. This has some
maintenance disadvantages, however - when we have several labels - it
is actually beneficial since we skip sending all label+scores down
the pipe and sorting them afterwards
Add missing bits of documentation
Remove this DEBUG nonsense
Cache the tally value inside the tally_for: key

This makes classify() scream while making the train() performance
slightly worse. I think it is a fair trade-off.
Merge branch 'no-cluster'

* no-cluster:
  Cache the tally value inside the tally_for: key
  Remove this DEBUG nonsense
  Add missing bits of documentation
  Make classify() not use scores() internally
  Make scores() not care about redis cluster
  Make _redis_script_load auto add namespace and labels
  Make train() and untrain() not care about redis cluster
  Make flush() not care about redis cluster
v0.0.3

        - Big performance improvements by caching the tally per label
        - Drop support for redis-cluster
        - Simple documentation fixes