WTF-389 Log an exception and terminate if widget config is invalid

If, on startup, a widget's positional configuration is invalid (ie:
cannot be displayed onscreen) then terminate the app and inform about
which widget is erroring

modules/gcal/display.go

@@ -32,7 +32,7 @@ func (widget *Widget) display() {
 	widget.mutex.Lock()
 	defer widget.mutex.Unlock()
 
-	widget.View.SetTitle(widget.ContextualTitle(widget.Name))
+	widget.View.SetTitle(widget.ContextualTitle(widget.Name()))
 	widget.View.SetText(widget.contentFrom(widget.calEvents))
 }