Allow to use authentication in "get token requests" to match OAuth2 RFC (#1514)
Allow to use authentication in "get token requests" to match OAuth2 RFC (#1514)

* Allow to use HTTP Basic auth for token request, as per RFC 6749, section 2.3.1

See https://tools.ietf.org/html/rfc6749#section-2.3.1

* Do not add Authorization header if no client_secret is present


hwi/HWIOAuthBundle