Fix #55 — The discover endpoint should define the list of available methods for a given MSISDN, MNC, MCC and roaming parameter.
Alexis review.
Remove /sms/mt/resend_code old API endpoint.
Merge pull request #62 from mozilla-services/remove_resend_code

Remove /sms/mt/resend_code old API endpoint.
Merge pull request #55 from mozilla-services/55-discover-endpoint

The /discover endpoint should return all available methods in a prefered order.
Refs #58 - Refs #59 — Link everything to hawkId.
Refs #59 — Upgrade the MOMT workflow.
Refs #52 — Have 6 digits lengths for short verification code.
Fix #56 — Be able to ask for long or short verificationCode. on /sms/mt/verify
Alexis review.