Removed unnecessary FunctionDelegate class
Removed makeFunction/Shading/Gradient methods in PDFFactory that were not used, duplicates of methods in (PDF)GradientFactory and getting in the way of refactoring


git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/branches/FOP-2393_gradient-rendering@1609745 13f79535-47bb-0310-9956-ffa450edef68