Improvements to the GQL tools

The GQL tool currently only supports full-text constraints ("jcr:contains"). I would like to add other constraints as well, for example "jcr:like". For that I would like to use the syntax

"jcr:nativeXPath":"jcr:like(@property, '%test%')"

For debugging and testing, I would like to have a way to get the XPath query instead of executing the query. Also, it would be nice to have a way to execute an XPath query, using the filter mechanism of this tool.

To simplify testing, the session should be optional.

The tool always adds an "order by" constraint. I would like to make this optional. The syntax is:

order:-

(currently, '-' is used to sort descending).