With this, we correctly show if an OOXML signature's metadata (e.g. comment) is valid or not. The <Manifest> element is still not checked yet, though -- and that contains the hashes of most interesting streams. Change-Id: Idd9e5a9072820c517974e26536aaf8eb9f34948a
Stuff for document signing. This code provides dialogs, and infrastructure wrapping libxmlsec that implements document signing.