twilio/twilio-php — pull request #141 by caseysoftware (2013-09-13 22:43:58+00:00)
Title: fixed the case where a 4xx error would not populate the exception properly and we'd end up with a wrong message

Credit goes to CostaC for his solution described here:
https://github.com/twilio/twilio-php/issues/133#issuecomment-21303014