Juan Pablo Ugarte authored Aug 01, 2018 and Juan Pablo Ugarte committed Aug 02, 2018

In order to support templates with abstract parents glade_widget_read()
will use a class with the GladeInstantiable prefix. So for a GtkBin
template it  will use GladeInstantiableGtkBin which of course has to
derive from GtkBin.

In turn glade_widget_write() will ommit GladeInstantiable prefix.