Request.get_normalized_parameters() is sorting and encoding parameters in the wrong order.

[gorakhargosh]

The OAuth 1.0 spec at http://tools.ietf.org/html/rfc5849#section-3.4.1.3.2 clearly states that the encoding is done before the sorting. python-oauth2 sorts before encoding. Also the tests for this routine are incorrect.

Please fix this line to sort after encoding. https://github.com/simplegeo/python-oauth2/blob/master/oauth2/init.py#L476

Cheers! Gora Khargosh.