[Java API] Add an executeTransaction Method


Within the current version of the Java API, there is a way to request a transaction without using Payment Passes, but there isn’t a way to execute a transaction with Payment Passes. There is a way to achieve this currently by using the REST API - https://docs.cubedpay.com/v0.1/reference#execute-transaction, and I feel as though this should be added to the Java API.


Hey Bert,

Just added this in the last commit 2f08a46.