`assertEquals()` is deprecated

[mtelka]

... and so tests fails with recent Python, for example:

__ BackwardsCompatibilityTestCase.test_incode_not_found_error_is_value_error ___

self = <ukpostcodeparser.test.parser.BackwardsCompatibilityTestCase testMethod=test_incode_not_found_error_is_value_error>

    def test_incode_not_found_error_is_value_error(self):
        """
        Previous iterations of the code raised a ValueError exception when incode was expected but
        not found.
        New exceptions should be caught in the same way in case any code relies on it.
        """

        with self.assertRaises(ValueError) as cm:
            parse_uk_postcode('N16', True, True)
>       self.assertEquals(cm.exception.__class__, IncodeNotFoundError)
        ^^^^^^^^^^^^^^^^^
E       AttributeError: 'BackwardsCompatibilityTestCase' object has no attribute 'assertEquals'. Did you mean: 'assertEqual'?

ukpostcodeparser/test/parser.py:21: AttributeError