Chile local flavor: New form select field: CLCommuneSelect

Included a list of commune as choices in localflavor/cl/cl_communes
Included a select field in localflavor/cl/forms.py

Also included a dict with the name of the communes mapping to the region
they belong to in localflavor/cl/cl_regions, in case someone wants to
validate the correspondence of the commune in the region.

Finnaly, changed the localflavor/cl/forms.py file to fit every line in
80 characters
Needs versionadded. Something [like this](https://github.com/django/django-localflavor/blob/d21205f68fdf1c132fd680404817313bd48c582e/localflavor/nl/models.py#L16).