[Review] Gobjectify PraghaToolbar

Turned perfectly to a GtkObject descendent of GTK_TOOLBAR. Is tested in gtk3 and gtk2 and working properly..

Only one detail.. When try to seek the song or show the remaining time, It takes a second (plus the delay of backend in seek the song) before updating the gui...
It may seem like a short time, but seems that the gui is not responding.. Before, where click in the progress bar, automatically updating the gui, and then waiting for the backend..

Could solved sending cwin to the signals, but prefer to prevent this.. because it would force me to make public the event_box's, and is not the idea!.. Any other ideas?.