`Transaction.equals` does not check all fields

## Problem

The `Transaction.equals` method checks for equality between two `Transaction` objects. Currently, many fields from the two transactions are checked, but there is a large number of fields (mostly app call transaction ones) which are **NOT** currently being checked.

## Scope

The `Transaction.equals` method _should_ check equality by checking all possible transaction fields.

Consider also an automated test which can somehow verify that each transaction field is checked by the `equals` method.