More fixes for order-dependent Jasmine spec failures

These ones would fail if `app.page` was in the wrong state from a previous test.

spec/javascripts/app/router_spec.js

@@ -1,4 +1,9 @@
 describe('app.Router', function () {
+  beforeEach(function () {
+    delete app.page;
+    new app.Router().stream();
+  });
+
   describe('followed_tags', function() {
     beforeEach(function() {
       loginAs({name: 'alice'});

spec/javascripts/app/views/stream/shortcuts_spec.js

@@ -2,6 +2,7 @@ describe("app.views.StreamShortcuts", function () {
 
   beforeEach(function() {
     // This puts `app.page` into the proper state.
+    delete app.page;
     new app.Router().stream();
 
     this.post1 = factory.post({author : factory.author({name : "Rebecca Black", id : 1492})});

spec/javascripts/app/views/stream_post_spec.js

@@ -1,5 +1,9 @@
 describe("app.views.StreamPost", function(){
   beforeEach(function(){
+    // This puts `app.page` into the proper state.
+    delete app.page;
+    new app.Router().stream();
+    
     this.PostViewClass = app.views.StreamPost;
 
     var posts = $.parseJSON(spec.readFixture("stream_json"));

spec/javascripts/app/views/stream_view_spec.js

@@ -1,6 +1,7 @@
 describe("app.views.Stream", function() {
   beforeEach(function() {
     // This puts `app.page` into the proper state.
+    delete app.page;
     new app.Router().stream();
 
     loginAs({name: "alice", avatar : {small : "http://avatar.com/photo.jpg"}});