Internal changes

Added a getTransformer() method to the net.sf.saxon.Filter class that is created in response to SAXTransformerFactory#newXMLFilter(). This allows setting of stylesheet parameters, a URIResolver, etc, when using this interface. Not tested.

The standard TraceListener now outputs an abbreviated version of the file name of the stylesheet module containing an instruction, as well as the line number.

The organization of the net.sf.saxon.functions package has changed. Much of the fixed information associated with individual functions is now contained in a static table in the module, rather than being returned by methods associated with each function. Most of the optimization methods (simplify, getDependencies, and reduce) now have a generic default implementation in the class, which most of the individual functions now use. This has reduced the overhead associated with implementing each function, which is important as the number of functions in XPath 2.0 has grown so much. It also creates further opportunities for combining the implementation of several related functions in one module, with better ability to share common code.

Unique document numbers are now allocated in the NamePool rather than the DocumentPool. This is visible in the results of generate-id(), because it means document numbers are not reset at the beginning of each transformation. This change has been made so that functions that rely on unique document numbers (for example, comparison of nodes into document order, or the union operation) can be done safely in a free-standing XPath environment. Eventually this will also allow document() to be executed outside an XSLT context - but not yet.