Moved djangorestframework into thirdpartylibs/.
Flattened the src/ hierarchy removing the toplevel. This will enable

us to have src/ directly on the path. Moved into new_src/, but I will
move it back to src/ after cleaning out the leftovers.
Moved the old src/<DIR>/README.rst into new_src/<DIR>/.
Removed the leftovers after the flattening of src/.
Moved new_src/ back to src/.
Made the changes required to requirements/ for the new src/ hierarchy.

Also added a setup.py to the root of the repo.
Added a tox.ini for flake8.