More or less complete usage example:

```py
        def process_transactions(transactions):
            mapper = PropertyMatcher()

            @mapper("transactionType=core:edge", "meta.edge:type=41")
            def edge(t):
                ''' match project edge transactions '''
                oldValue = [PHIDRef(p) for p in t["oldValue"]]
                newValue = [PHIDRef(p) for p in t["newValue"]]
                return [["projects", '', oldValue, newValue]]

            for taskid, t in transactions.result.items():
                st = sorted(t, key=itemgetter("dateCreated"))
                for record in st:
                    for row in mapper.run(record):
                        if row:
                            yield row

        transactions = get_some_transactions()

        for row in process_transactions(transactions):
            ''' do something with row '''
```

Change-Id: I6eac22574b02df75b9fd8c38d1a29856dd05f130