Bump version to 2.3.1
Added the Phone Verification/Intelligence endpoints

Usage:
     # Send the verification code
     Authy::PhoneIntelligence.verification_start(
       :via => "sms",
       :country_code => "1",
       :phone_number => "111-111-1111"
      )

     # Verifying the verification code
     Authy::PhoneVerification.verification_check(
       :country_code => "1",
       :phone_number => "111-111-1111",
       :verification_code => "1234"
     )

     # Requesting the phone number information
     Authy::PhoneIntelligence.info(
       :phone_number => "111-111-1111",
       :country_code => "1"
     )

Conflicts:
	spec/authy/api_spec.rb
Fixed provider and ported expectations.

In order to be consistent with the sandbox api data, `provider` was
changed to Google Voice, and `ported` to false.
Merge remote-tracking branch 'origin/phone-intelligence'