Travis fail to install django-inspectional-registration #19

Fix #19 

The following are critical changes

- Now `python setup.py install` command **do not** re-compile messages
- Now `python setup.py sdist` command **do not** remove `.mo` files and **do** re-compile messages
- `python setup.py publish` is replaced by `alias` command and defined in `setup.cfg`
- Now sdist **do** include `.po` and `.mo` files