Move scanner preferences page to GtkBuilder
Move confirmation preferences page to GtkBuilder
Move UI and misc preferences pages to GtkBuilder

Unify the UI settings in a single User Interface page.
Move file preferences page to GtkBuilder
Move tags preferences page to GtkBuilder
Move ID3 preferences page to GtkBuilder
Move CDDB preferences page to GtkBuilder
Move preferences notebook into GtkBuilder
Remove redundant et_grid_new() define

Call gtk_grid_new() directly.
Remove unnecessary et_grid_attach_margins()
Remove old GTK+ 2 grid compatibility code
Move playlist dialog to GtkBuilder
Move rename directory dialog to GtkBuilder
Set transient parents before init()

If gtk_window_set_transient_for() is called in the GObject init()
method, it is overridden to the default for the property immediately
afterwards, as "transient-for" is a contruct property.  Instead, set the
property as part of calls to g_object_new().
Move picture details dialog to GtkBuilder
Move browse directory dialog to GtkBuilder
Move open files dialog to GtkBuilder
Move search dialog to GtkBuilder
Move load files dialog to GtkBuilder