Multipe domain & wildcard support for CORS

[dschep]

Enable usage like this, list of domains & support wildcards in strings:

    >>> @cors_headers(origin=['https://example.com', 'https://*.example.com'])
    ... def hello_custom_origin(example, context):
    ...     return {'body': 'foobar'}
    >>> hello_custom_origin({'headers': {'Host': 'https://foobar.example.com'}}, object())
    {'body': 'foobar', 'headers': {'Access-Control-Allow-Origin': 'https://foobar.example.com'}