Spinner: Define defaults for callbacks.

tests/unit/spinner/spinner_defaults.js

@@ -10,6 +10,10 @@ commonWidgetTests( "spinner", {
 		value: null,
 
 		// callbacks
-		create: null
+		change: null,
+		create: null,
+		spin: null,
+		start: null,
+		stop: null
 	}
 });

ui/jquery.ui.spinner.js

@@ -24,7 +24,12 @@ $.widget( "ui.spinner", {
 		numberFormat: null,
 		page: 10,
 		step: null,
-		value: null
+		value: null,
+
+		change: null,
+		spin: null,
+		start: null,
+		stop: null
 	},
 
 	_create: function() {