Revision 152661

Added input module that resolves to a real path similar to the 
RealPathModules but by use of a SourceResolver instead of the 
Context object (which always resolves to the context path). This allows 
to mount apps external of the servlet context path and still have a 
correct real path resolved in respect to the sitemap calling the module. 
As I couldn't fix the RealPathModule in a backward compatible way, 
becasuse {realpath:/} and {realpath:.} both resolve to the context 
root whereas {contextpath:/} resolves to the context root but 
{contextpath:.} resolves to the path of the respective sitemap, I've 
choosen to create a new Module for it.