Use get_internal_wsgi_application in Django 1.4

[streeter]

Mimic the runserver command that ships in Django 1.4 and up more closely. By default, that command gets the WSGI handler by calling get_internal_wsgi_application(). Without this change, the runserver command ignores the WSGI_APPLICATION setting in Django 1.4. By ignoring the setting, the runserver command will not apply any WSGI middleware in the wsgi.py file.

If get_internal_wsgi_application is not available for import, revert back to the previous WSGIHandler() function.

[travisbot]

This pull request fails (merged 4838550b into b1540da3).

[travisbot]

This pull request fails (merged 80e7a0aa into b1540da3).

[streeter]

So I ran make test on all three supported Django versions, and they passed. It looks like the flake8 tests are failing, but not for reasons in this this pull request.

[jezdez]

Yeah, this is expected, flake8 got much more pedantic recently, I'll fix this before merging.

[streeter]

You don't have to pull in 80e7a0a as it was an attempt to quell (what I thought) was the flake8 error.