fix NWS samecode url

I was getting started with this project and noticed that the unit tests for geo.py and weatheralerts.py were failing.

    ======================================================================
    ERROR: test_samecode_lookup_false (__main__.Test_GeoDB)
    ----------------------------------------------------------------------
    Traceback (most recent call last):
      File "test_geodb.py", line 9, in setUp
        self.geo = GeoDB()
      File "weatheralerts\geo.py", line
    16, in __init__
        self.__same = SameCodes()
      File "weatheralerts\geo.py", line
    93, in __init__
        self._load_same_codes()
      File "weatheralerts\geo.py", line
    109, in _load_same_codes
        self._cached_same_codes()
      File "weatheralerts\geo.py", line
    149, in _cached_same_codes
        self.reload()
      File "weatheralerts\geo.py", line
    102, in reload
        self._load_same_codes(refresh=True)
      File "weatheralerts\geo.py", line
    107, in _load_same_codes
        self._get_same_codes()
      File "weatheralerts\geo.py", line
    119, in _get_same_codes
        code, local, state = str(row).strip().split(',')
    ValueError: need more than 1 value to unpack

    ----------------------------------------------------------------------
    Ran 8 tests in 0.512s

    FAILED (errors=8)


It seems the HTTP call made in _get_same_codes() is to a dead url, found the new location here: http://www.nws.noaa.gov/nwr/data/SameCode.txt. All tests passing again after this update.