Added a utils.py get_states_of_brazil

[vic012]

All Changes
I Added a utils.py file to localflavor.br initially with a method called get_states_of_brazil. Through this method, the user can get the state through a (federative_unit - str) and can configure the return to be upper or lower case. If the federative_unit is None or if its value is not in the available state options, a dict will be returned with all states of Brazil.

• [x ] Add an entry to the docs/changelog.rst describing the change.

• [x ] Add an entry for your name in the docs/authors.rst file if it's not
  already there.

[leogregianin]

Useful for many applications

[benkonrath]

@vic012 Can you provide some information about how this fits into django-localflavor? Reading through get_states_of_brazil(), it seems to be a helper function / application specific logic, rather than something connected to a Django model or form. I don't use the Brazil locolflavor personally, so I don't know how it's useful to developers in Brazil who use the BR flavor. Thanks.