Allow stubModules to be configured for r.js.

@@ -638,6 +638,7 @@ module.exports = function (grunt) {
                             'defaults': 'empty:',
                             'defaults': 'empty:',
                         }, mpConfig.requirePaths),
                         }, mpConfig.requirePaths),
                         modules: mpConfig.modules,
                         modules: mpConfig.modules,
+                        stubModules: mpConfig.stubModules,
                     },
                     },
                 }
                 }
             };
             };