* Ensure payments, invoice and credit amount balance in the validator prior to saving
* additional payment validation rules and tests for processing payments
* Factories for credits
* Tests for payments
* Working on updating a payment
* Working on updating a payment
* fixes for updating a payment
* Working on Payment Tests
* More tests for payments, formrequests
* remove product_key as required from products
* Remove unnecessary save() on invoice
* Update copyright
* Working on Credit Repository
* Implement credits as a paymentable entity
* Add credit_id to transformer
* fix rules for update payment
* Fix random deleted_at keys in transformers
* Fix for password_protect check
* Refactor company properties to be presented from settings object instead of company properties
* Working on Email Tests
* Working on emails
* Working on email templats
* Include text version of email
* Refactor Email template builder into trait'
* Fix for custom_value4
* Refactor payment_date -> date && payment_type_id -> type_id
* expose paymentables to API
* expose paymentables to API
* Implement a next_send_date field in invoice/quote tables to allow control over reminder scheduling
* Add custom_values to users,documents and company_gateways tables
