Verapdf claims PDF-A/3s created witth visualize are invalid

[jstaerk]

Specification: ISO 19005-3:2012, Clause: 6.6.2.3.1, Test number:2

Could be an issue in, from, or related to Apache fop, upstreamed as https://issues.apache.org/jira/browse/FOP-3214

[jstaerk]

+upstreamed at itplr-kosit/xrechnung-visualization#16