gtkbuilder: add accessibility role declaration
This allows to override the role declared to the atk stack. For instance,
allows to tell the accessibility stack that a label is just a message in a message box.
Fixes #109 (closed)
This allows to override the role declared to the atk stack. For instance,
allows to tell the accessibility stack that a label is just a message in a message box.
Fixes #109 (closed)