Added image url and onerror, onload events on callbacks

[mbarzda]

Error and success callbacks should have image url and event parameters for more detailed information purposes.

[eddhannay]

This would be really helpful, for example when Adblock Plus blocks a lazy-loaded image. I was going to propose a patch where removing the options.src attribute was done after the error call, but this would be much cleaner.

[dinbror]

Fixed in v. 1.5.3