#882 "Full portlet: PDF output fails"

- see notes in comment
- instead of creating a single WebAppContext, we create one per servlet/portlet/filter
- listeners wrap as they go
- this is ok as it's a pretty lightweight wrapper
- attributes remain shared per web app
- whether Orbeon was already initialized is stored in the shared context
- this ensures that an incoming servlet vs. portlet request finds a compatible native context when needed
Add xxf:get-portlet-mode()/xxf:get-window-state()
#1037 "Upload broken with full portlet"

This was due to the use of oxf:request, which reads the request body and
then closes the stream. With new new Upload, we want to stream the body
ourselves, so we can handle upload progress information.
#1038 "Full portlet: Saving image attachment fails"

LocalRequest does not reset request attributes (which may or may not be
the right thing to do), so the shortcut to the request body must not be
stored there. Storing in PipelineContext instead. See also comments.