Out of date README.rst still refers to QueuedSearchIndex

[gremmie]

I think the README.rst might be out of date for Haystack 2.x.

This part:

Alter all of your SearchIndex subclasses to inherit from queued_search.indexes.QueuedSearchIndex (as well as indexes.Indexable).

should maybe read:

In your settings.py:

HAYSTACK_SIGNAL_PROCESSOR = 'queued_search.signals.QueuedSignalProcessor'