1.4.0 (stable) 2016-09-19

This brings us up to API v2.3

• Exposed subscription 'PlanCode' publicly #139
• Set AddOn#PlanCode for GetAddOn #141
• Fix TLS preferences for releases #143
• Adding cc_emails attribute to Account class #147
• Fixed Get Adjustment and related test #150
• Add Currency attribute to BillingInfo #151
• Update to API version 2.2 #154
• Adding PaymentMethod attribute on Transaction #159
• Update to config with API Access #162
• Add error case for 400 status code #164
• Usage Based Billing Support #165