This module exec’s a script (or binary), specified by the ‘path’
attribute in the configuration.
It then reads tags from the script’s stdout.
The format of the output is:
tag|type|value
tag|type|value
<empty line>
I.e. the script writes N tags followed by an empty line. This
constitutes a transaction.
When a new transaction is received, its tags replaces *all* previous
tags.
