Add missing Payer, Sale, Address, Transaction attributes

Added some attributes that are described in https://developer.paypal.com/docs/api/, but missing from data type definitions.

It solves following errors:
```
undefined method `status=' for #<PayPal::SDK::REST::DataTypes::Payer:0xbd52aa4>
undefined method `recipient_name=' for #<PayPal::SDK::REST::DataTypes::Address:0xbd51cbc>
undefined method `payment_mode=' for #<PayPal::SDK::REST::DataTypes::Sale:0xbd50934>
undefined method `protection_eligibility=' for #<PayPal::SDK::REST::DataTypes::Sale:0xbd50934>
undefined method `protection_eligibility_type=' for #<PayPal::SDK::REST::DataTypes::Sale:0xbd50934>
```