transition updates

ionic/transitions/transition.js

@@ -0,0 +1,23 @@
+
+let registry = {};
+
+class TransitionController {
+
+  create(navCtrl, opts = {}) {
+    let name = opts.animation || 'ios';
+
+    let TransitionClass = registry[name];
+    if (!TransitionClass) {
+      TransitionClass = registry['none'];
+    }
+
+    return new TransitionClass(navCtrl, opts);
+  }
+
+  register(name, transitionClass) {
+    registry[name] = transitionClass;
+  }
+
+}
+
+export let Transition = new TransitionController();