editable installation requires a specific directory layout

ansible-requirements.txt

 Jinja2==2.6
 PyYAML==3.10
--e git://github.com/ansible/ansible@8e7dc3c79cb3a3d109c74e346c8dab3479bd5e77#egg=ansible
+# http://stackoverflow.com/questions/11597103/modify-setup-py-to-support-pip-install-from-github
+git+git://github.com/ansible/ansible@devel#egg=ansible
 argparse==1.2.1
 boto==2.8.0
 paramiko==1.10.1