Filter layer content with "query builder"

In keeping with the theme of putting users in charge a long standing ability available to developers has been the ability to limit the features provided to a layer up front (ie before SLD).

Indeed it has been a training exercise in the uDig course to produce a style configurator for this already existing functionality.

I put one together and added it to the application built around FilterViewer - a query build used to produce filter that offers command completion, full list of the CQL functions, and list of the current features attributes.

All in all I hope this one is useful.