Fix angular 1.2 examples with duplicate items

Close #726

architecture-examples/angularjs-perf/index.html

@@ -19,7 +19,7 @@
 				<input id="toggle-all" type="checkbox" ng-model="allChecked" ng-click="markAll(allChecked)">
 				<label for="toggle-all">Mark all as complete</label>
 				<ul id="todo-list">
-					<li ng-repeat="todo in todos | filter:statusFilter" ng-class="{completed: todo.completed, editing: todo == editedTodo}">
+					<li ng-repeat="todo in todos | filter:statusFilter track by $index" ng-class="{completed: todo.completed, editing: todo == editedTodo}">
 						<div class="view">
 							<input class="toggle" type="checkbox" ng-model="todo.completed" ng-change="todoCompleted(todo)">
 							<label ng-dblclick="editTodo(todo)">{{todo.title}}</label>

architecture-examples/angularjs/index.html

@@ -19,7 +19,7 @@
 				<input id="toggle-all" type="checkbox" ng-model="allChecked" ng-click="markAll(allChecked)">
 				<label for="toggle-all">Mark all as complete</label>
 				<ul id="todo-list">
-					<li ng-repeat="todo in todos | filter:statusFilter" ng-class="{completed: todo.completed, editing: todo == editedTodo}">
+					<li ng-repeat="todo in todos | filter:statusFilter track by $index" ng-class="{completed: todo.completed, editing: todo == editedTodo}">
 						<div class="view">
 							<input class="toggle" type="checkbox" ng-model="todo.completed">
 							<label ng-dblclick="editTodo(todo)">{{todo.title}}</label>

labs/dependency-examples/angularjs_require/index.html

@@ -28,7 +28,7 @@
 				<input id="toggle-all" type="checkbox" ng-model="allChecked" ng-click="markAll(allChecked)">
 				<label for="toggle-all">Mark all as complete</label>
 				<ul id="todo-list">
-					<li ng-repeat="todo in todos | filter:statusFilter" ng-class="{completed: todo.completed, editing: todo == editedTodo}">
+					<li ng-repeat="todo in todos | filter:statusFilter track by $index" ng-class="{completed: todo.completed, editing: todo == editedTodo}">
 						<div class="view">
 							<input class="toggle" type="checkbox" ng-model="todo.completed">
 							<label ng-dblclick="editTodo(todo)">{{todo.title}}</label>