Memory leak warnings associated with ViewBox

[David Mathog]

The introduction of the "ViewBox" function is producing "memory possibly lost" warnings when testing emf and wmf files in valgrind. In previous versions the end of EMf::open in emf-inout.cpp was just:

    d.tri = trinfo_release_except_FC(d.tri);
    return doc;
}

Now there is a ~25 line block between those two lines where a bunch of ViewBox and doc actions are performed. In that section, these lines leak:

        doc->ensureUpToDate();

        repr->setAttribute("inkscape:document-units", os.str().c_str());

        doc->setViewBox(Geom::Rect::from_xywh(0, 0, doc->getWidth().value(doc_unit), doc->getHeight().value(doc_unit)));

        doc->getRoot()->scaleChildItemsRec(Geom::Scale(scale), Geom::Point(0, SP_ACTIVE_DOCUMENT->getHeight().value("px")));

        doc->ensureUpToDate();

That is, roughly every 3rd line in this section of code. The memory lost (maybe) is small, I think 16 bytes in each case.

There is also an ensureUpToDate() call in Emf::print_document_to_file and that one did not trigger one of these warnings, and I know that section was exercised because of the valgrind warning for set_param_string() a few lines away. (That is an old bug, I forget the number.)