Helper class to programmatically handle the OpenID 2.0 HTML Form
redirection. The class can be added and if needed it will intercept and
perform the post on behalf of the end user. In normal operation a browser
would automatically post the form.
There is no harm in having the forwarder in place even if there is no
post there then the code would be skipped.
input - - html form to post
resource - - existing or null
response from OpenID OP
java.io.IOException - - on failed html xml parsing.