Changes for Unique 3.0.0
========================
• Set default DBus timeout to 3 seconds [Bill Nottingham]
• Fix introspection annotations [Luciana Fujii Pontello]
• Use GTK_CHECK_BACKEND to enable X11-specific API usage
• Fix signedness of the lenght parameter of UniqueMessageData.set()
• Bail out of UniqueMessageData.get_text_plain() if the message is empty
• Fix the help string of the --enable-maintainer-flags configure switch
• Update the documentation
• Use the gobject-introspection Makefile template to generate
 introspection files
• Correctly version the API reference, to avoid collisions with the
 gtk2.x series