Version 2.4.0

• Force cURL to validate SSL certificates #122
• Reverted #64, removing balance_in_cents_invoiced and balance_in_cents_uninvoiced from Recurly_Account. They were never added to the API.
• Added tax_code to Recurly_Plan, Recurly_Addon and Recurly_Adjustment #120
• Added invoice previews: Recurly_Invoice::previewPendingCharges($accountCode) #112
• Added terms_and_conditions and customer_notes to Recurly_Invoice #115
• Added vat_location_valid field to Recurly_Account #127
• Added updateNotes() and vat_reverse_charge to Recurly_Subscription. #128
• Added vat_reverse_charge_notes to Recurly_Invoice. #128
• Added invoice_number_prefix and invoiceNumberWithPrefix() to Recurly_Invoice. This is to be used with the Country Invoice Sequencing feature. #130