Country aliases not resolved on normalization

[kdeldycke]

Non standard, addresses' country code are not normalized to their good values, even if defined as alias in territory.py:

>>> import postal_address
>>> postal_address.__version__
'0.7.1'
>>> from postal_address import Address
>>> Address(country_code='EL')
  File "(...)/postal_address-0.7.1-py2.7.egg/postal_address/address.py", line 152, in __repr__
  File "(...)/postal_address-0.7.1-py2.7.egg/postal_address/address.py", line 456, in country_name
  File "(...)/postal_address-0.7.1-py2.7.egg/postal_address/address.py", line 445, in country
  File "(...)/pycountry-1.10-py2.7.egg/pycountry/db.py", line 114, in get
    return self.indices[field][value]
KeyError: 'EL'