ZF-2499: Consumer::verify() could be more verbose.

Description

Consumer::verify() can return false in 11 different places. It would easily be my favorite OpenID library if it returned an error code or threw an exception instead of just returning false. This would make implementing and debugging consumer/provider code much friendlier.

Comments

I'm not sure how feasible it would be, but could verify possibly return Zend_Auth_Result?

it should also throw a Zend_OpenId_Exception in the places where it currently return false.

Now Zend_OpenId_Consumer::getError() may return explanation in case of login(), check() or verify() failure.

Updating for the 1.6.0 release.