Fix #154

[michalsn]

This one fixes #154.

I'm not quite sure if validate method shoud contains isThrottled check... maybe someone can came up with scenario where this behavior will be an issue?

[lonnieezell]

Originally I was thinking that validate() could be used as a standalone method where it would be bad to have the isThrottled check in there... but I can't think of why I was thinking that at the time.

At some point, I'd like to get the whole throttling process moved to it's own library that can be used elsewhere, but need to do some more studying up on the best way to handle that site-wide.

[michalsn]

Well... so far I couldn't find any other use case for validate method.

Another possibility is to add one more parameter i.e. validate($credentials, $return_user=false, $record=true) - a little ugly but will work.