Honor "use-stock" property for the HildonButton title
Honor "use-stock" property for the HildonButton title

If GtkButton:use-stock is %TRUE, look up for the string in the title
in the stock.

android-808/libhildon,Cordia/libhildon,Cordia/libhildon,android-808/libhildon,Cordia/libhildon,android-808/libhildon