An early draft name for Passepartout was "Framer" since it deals with frames. (We like FrameMaker a lot, not that it has much in common with Passepartout.) This was a very dull name, so we changed it. A passepartout is a kind of cardboard frame you put around watercolour paintings.
You don't. You write the text in XML format in your favourite text editor, then you import the text into Passepartout. Read the User's Guide for more detailed instructions.
Not at all. Text is only imported by reference. If you edit and save changes to the XML file, Passepartout will notice the change and update the display.
Any Passepartout release will only build with exactly the version or versions of libxml++ that are specified in the INSTALL file. The libxml++ library is currently undergoing rapid development. As soon as the libxml++ team makes a stable release this will no longer be a problem.