Please allow qdbuscpp2xml to understand simple, custom types

It would be very helpful to me if qtdbuscpp2xml were able to annotate the resulting XML with custom, but simple, types. In other words, with types which are derived by using typedef on an already-dbus-compatible type.

I am working on a Qt-based application which makes significant use of DBus. On DBus, I pass simple things like QStrings, qint32, and qint64. These all mean more to me than simple numbers. Some are IDs, others are timestamps, and some are human-readable.

It would help me keep track of what is going on if I were able to `typedef fooID_t qint64` and then be able to pass this on DBus. I use qtdbuscpp2xml and qtdbusxml2cpp to generate DBus interfaces. Unfortunately, the qtdbuscpp2xml step is not able to handle typedefs, even for simple types. I could fix the xml by hand, but that sounds like something a machine should be able to do for me!

For my real-world use-case, please see here: https://phabricator.kde.org/D17553 . I have many similar types in the same program which I would love to be able to name!