refactor(forEach): change to for-of with iterable

rename: foreach -> for
rename: array -> iterable
update: DartParseTreeWriter
update: naive_infinite_scroll
update: todo
fix: tests in foreach_spec

Closes #919

modules/examples/src/todo/index.js

@@ -1,4 +1,4 @@
-import {bootstrap, Component, Template, Foreach} from 'angular2/angular2';
+import {bootstrap, Component, Template, For} from 'angular2/angular2';
 import {Store, Todo, TodoFactory} from './services/TodoStore';
 
 @Component({
@@ -10,7 +10,7 @@ import {Store, Todo, TodoFactory} from './services/TodoStore';
 })
 @Template({
   url: 'todo.html',
-  directives: [Foreach]
+  directives: [For]
 })
 class TodoApp {
   todoStore: Store;

modules/examples/src/todo/todo.html

@@ -18,7 +18,7 @@
 
     <ul id="todo-list">
 
-      <li *foreach="#todo in todoStore.list">
+      <li *for="#todo of todoStore.list">
 
         <div class="view"
             [class.hidden]="todoEdit == todo">