fix Yahoo OpenID not working on newer versions of PHP/cURL.
fix A warning when the realm is shorter than 8 chars.
fix Use cURL when 'allow_url_fopen' is disabled.
fix Different POST-behavior when using cURL and streams.
fix Avoid hiding the real presence/absence of fields.
add Added User-Agent header for better compatibility.
add Added 'text/html' to the discovery content-types.
add Added support for Composer (dependency manager).
add Added ability to set the 'CN_match' SSL option.
fix Fixed a bug in the proxy configuration.
add Added support for overriding the initial URL XRDS lookup.
add Added support for connecting through a proxy.
add Added support for an OpenID+OAuth hybrid protocol.
add Added SSL-validation support for HEAD-requests.
fix Fixed a bug in the attribute exchange implementation.
fix Fixed a bug in stream defaults after a HEAD request.
fix Fixed a bug causing validation failure when using streams.