Add output for 'File' XML elements
Add output for 'File' XML elements

Add a queue of source files encountered during AST traversal.  Print
them in the XML output as 'File' elements like those produced by gccxml.

ellert/CastXML,iMichka/CastXML,CastXML/CastXML,ellert/CastXML,iMichka/CastXML,thewtex/CastXML,ellert/CastXML,bradking/CastXML,thewtex/CastXML,bradking/CastXML,thewtex/CastXML,bradking/CastXML,CastXML/CastXML,CastXML/CastXML