Bumping version to 0.9.2 alpha.
South support

This commit adds support for South. All django-pg fields,
including CompositeField subclasses, will "just work" with
South migrations.
JSON Field Support

This commit adds support for JSON Fields. JSON Fields are declared
using `models.JSONField` and take their Python counterparts as values,
and are serialized to JSON in order to go into the database.
Reorganizing docs.

The Sphinx default organization was right; I was wrong. I readily admit
it.

This commit changes me back to the Sphinx default organization.
Fixed an awkward phrase in docs.
Bumping version to 0.9.2 final.
Merge branch 'master' into stable/0.9.x