refactor(core): move more modules into core

modules/angular2/src/core/change_detection.ts

@@ -0,0 +1,27 @@
+/**
+ * @module
+ * @description
+ * Change detection enables data binding in Angular.
+ */
+
+export {
+  ChangeDetectionStrategy,
+
+  ExpressionChangedAfterItHasBeenCheckedException,
+  ChangeDetectionError,
+
+  ChangeDetector,
+  Locals,
+  ChangeDetectorRef,
+
+  WrappedValue,
+  PipeTransform,
+  PipeOnDestroy,
+  IterableDiffers,
+  IterableDiffer,
+  IterableDifferFactory,
+  KeyValueDiffers,
+  KeyValueDiffer,
+  KeyValueDifferFactory
+
+} from 'angular2/src/core/change_detection/change_detection';