Fixed indentation of example in tutuorial 2.
Removed import * in tests.

Thanks to flake8 path/to/file.py | awk -F ' ' '{ print $5 }' | sort | uniq
Fixed #5789 -- Changed LocaleMiddleware session variable to '_language'.

The old 'django_language' variable will still be read from in order
to migrate users. The backwards-compatability shim will be removed in
Django 1.8.

Thanks to jdunck for the report and stugots for the initial patch.
Fixed E221 pep8 warnings.
Removed unused imports (or marked them flake8 ignore).