Experimental: do not disable south migrations

Ref: https://github.com/pelme/pytest_django/issues/128
Fix south integration with `--create-db`

This requires to monkey-patch `south.hacks.django_1_0.SkipFlushCommand`,
which has a bug that prevents any initial data to be installed.

South issue: http://south.aeracode.org/ticket/1395#comment:3

Fixes https://github.com/pelme/pytest_django/pull/22

Django code reference for 1.6, from
django-1.6.x/django/db/backends/creation.py(339)create_test_db():

    # Report syncdb messages at one level lower than that requested.
    # This ensures we don't get flooded with messages during testing
    # (unless you really ask to be flooded)
    call_command('syncdb',
        verbosity=max(verbosity - 1, 0),
        interactive=False,
        database=self.connection.alias,
        load_initial_data=False)

    # We need to then do a flush to ensure that any data installed by
    # custom SQL has been removed. The only test data should come from
    # test fixtures, or autogenerated from post_syncdb triggers.
    # This has the side effect of loading initial data (which was
    # intentionally skipped in the syncdb).
    call_command('flush',
        verbosity=max(verbosity - 1, 0),
        interactive=False,
        database=self.connection.alias)
Merge pull request #129 from blueyed/do-not-disable-south

Handle south migrations
Remove unnecessary assignment in conftest
Move django.setup() to right after settings. Refs #119.
This patch is still not working properly with regard to loading settings
from within the test directories.
Remove support for having settings within test directories
Fix for error message for invalid settings
Call django.setup() directly after configuring settings
Added changelog entry for #119, #134