Build: Put all AMD modules in "src/" in strict mode

Fixes gh-3073

src/data/Data.js

@@ -4,6 +4,8 @@ define( [
 	"./var/acceptData"
 ], function( jQuery, rnotwhite, acceptData ) {
 
+"use strict";
+
 function Data() {
 	this.expando = jQuery.expando + Data.uid++;
 }

src/data/var/acceptData.js

@@ -1,5 +1,7 @@
 define( function() {
 
+"use strict";
+
 /**
  * Determines whether an object can have data
  */

src/data/var/dataPriv.js

@@ -1,5 +1,7 @@
 define( [
 	"../Data"
 ], function( Data ) {
+	"use strict";
+
 	return new Data();
 } );

src/data/var/dataUser.js

@@ -1,5 +1,7 @@
 define( [
 	"../Data"
 ], function( Data ) {
+	"use strict";
+
 	return new Data();
 } );