fix(urlRouter): allow .when() to redirect, even after a successful $state.go()

- This partially reverts a change from 0.2.13 intended to stop infinite redirects.
  - b267ecd
  - #1573
- This will be likely be re-reverted in 1.0

Closes #1584

Author: christopherthielen

src/urlRouter.js

@@ -279,7 +279,8 @@ function $UrlRouterProvider(   $locationProvider,   $urlMatcherFactory) {
       if (evt && evt.defaultPrevented) return;
       var ignoreUpdate = lastPushedUrl && $location.url() === lastPushedUrl;
       lastPushedUrl = undefined;
-      if (ignoreUpdate) return true;
+      // TODO: Re-implement this in 1.0 for https://github.com/angular-ui/ui-router/issues/1573
+      //if (ignoreUpdate) return true;
 
       function check(rule) {
         var handled = rule($injector, $location);