Added input parameter to FunctionTransform
* the external "transform" function now expects a input document as its first parameter
** this input parameter is resolved and passed as input to the transformation
** changed and expanded test case accordingly
* because of xalan internal problem this currently only supports input DOMs loaded directly from the fs
** passing result trees or node sets analog to how the transformation may be passed into the function leads to parsing and assert failures
** parsing node-based input DOMs using xalanc::XalanTransformer::parseSource produces errors concerning base entity resolution
** if the error capacitor instance is temporarily disabled it works correctly as long as one doesn't try to access the input document
*** this causes a assert failure in the XPath implementation (seems to be related to XALANC-540)