Adds partial documentation tex file to the clean target

Makefile

@@ -49,6 +49,7 @@ clean:
 	@echo Cleaning $(TOP) and $(NEEDED)
 	@$(foreach file,$(TOP_NAME) $(TOP_NAME)-slide2 preview texput,$(foreach ext,$(EXT),[ -e $(file).$(ext) ] && rm -f $(file).$(ext) || true;))
 	@rm -f $(NEEDED)
+	@rm -f $(patsubst %.pdf, %.tex, $(NEEDED_DOC))
 
 
 %.pdftex:%.fig