Option to dump all fixture_gen.py functions at once

[blanchardjeremy]

I'd like to be able to run the command and dump all of my fixtures at once without specifying them all manually.

This would require two new functions

manage.py generate_fixture myapp  # finds all the functions in myapp and generates a fixture for all of them
manage.py generate_fixture  # finds all the fixture_gen.py files and all the functions in them

Thanks!