Have Windward's ForEAch tag behave consistently towards empty collections.

In XSLT as in any programming language where a "foreach" like operator exists, when the collection to loop over is empty, the loop iterates 0 times.

Take for instance this XSLT:
https://xsltfiddle.liberty-development.net/gWmsLAH
Change the XML to contain no Book elements. It will iterate 0 times.

Windward behaves differently. Sometimes. Sometimes it iterates 0 times as expected. Sometimes it raises an exception, making Windward unpredictable and unreliable.
See https://support.apryse.com/support/tickets/50936

My improvment idea: make Windward predictable en reliable by having it implement the expected behaviour in all cases: iterate 0 times over empty collections without raising errors.