fix(transition): always use animation, just no duration

Closes #227

ionic/components/nav/nav-controller.ts

@@ -69,7 +69,7 @@ export class NavController extends Ion {
 
     // do not animate if this is the first in the stack
     if (!this.views.length) {
-      opts.animation = 'none';
+      opts.animate = false;
     }
 
     // default the direction to "forward"
@@ -269,15 +269,10 @@ export class NavController extends Ion {
       return callback();
     }
 
-    if (opts.animate === false) {
-      opts.animation = 'none';
-
-    } else if (!opts.animation) {
+    if (!opts.animation) {
       opts.animation = this.config.setting('viewTransition');
     }
 
-    opts.animate = (opts.animation !== 'none');
-
     // wait for the new view to complete setup
     enteringView.stage(() => {
 
@@ -295,7 +290,7 @@ export class NavController extends Ion {
 
         // init the transition animation
         let transAnimation = Transition.create(this, opts);
-        if (!opts.animate) {
+        if (opts.animate === false) {
           // force it to not animate the elements, just apply the "to" styles
           transAnimation.duration(0);
         }

ionic/components/nav/view-controller.ts

@@ -210,15 +210,6 @@ export class ViewController {
     }
   }
 
-  /**
-   * TODO
-   * @returns {TODO} TODO
-   */
-  postRender() {
-    // the elements are in the DOM and the browser
-    // has rendered them in their correct locations
-  }
-
 
   /**
    * The view has loaded. This event only happens once per view being