docs(user-guide): update Dart text to match new TS text

also update the Dart sample a bit

closes #677

Author: kwalrath

public/docs/_examples/user-input/dart/lib/app_component.dart

@@ -1,16 +1,15 @@
 // #docregion
-library user_input.app_component;
-
 import 'package:angular2/angular2.dart';
-import 'package:user_input/click_me_component.dart';
-import 'package:user_input/click_me_component_2.dart';
-import 'package:user_input/loop_back_component.dart';
-import 'package:user_input/key_up_components.dart';
-import 'package:user_input/little_tour_component.dart';
+
+import 'click_me_component.dart';
+import 'click_me_component_2.dart';
+import 'loop_back_component.dart';
+import 'keyup_components.dart';
+import 'little_tour_component.dart';
 
 @Component(
     selector: 'my-app',
-    templateUrl: 'app-component.html',
+    templateUrl: 'app_component.html',
     directives: const [
       ClickMeComponent,
       ClickMeComponent2,

public/docs/_examples/user-input/dart/lib/app-component.html renamed to public/docs/_examples/user-input/dart/lib/app_component.html

@@ -1,12 +1,13 @@
 // #docregion
-library user_input.click_me_component;
-
 import 'package:angular2/angular2.dart';
 
 // #docregion click-me-component
 @Component(
     selector: 'click-me',
-    template: '''<button (click)="onClickMe()">Click me!</button>
+    template: '''
+    // #docregion click-me-button
+    <button (click)="onClickMe()">Click me!</button>
+    // #enddocregion click-me-button
     {{clickMessage}}''')
 class ClickMeComponent {
   String clickMessage = '';

public/docs/_examples/user-input/dart/lib/click_me_component.dart

@@ -1,6 +1,4 @@
 // #docregion
-library user_input.click_me_component_2;
-
 import 'package:angular2/angular2.dart';
 
 @Component(

public/docs/_examples/user-input/dart/lib/click_me_component_2.dart

@@ -1,7 +1,5 @@
 // #docplaster
 // #docregion
-library user_input.key_up_components;
-
 import 'dart:html';
 
 import 'package:angular2/angular2.dart';

public/docs/_examples/user-input/dart/lib/key_up_components.dart renamed to public/docs/_examples/user-input/dart/lib/keyup_components.dart

@@ -1,8 +1,4 @@
 // #docregion
-library user_input.little_tour_component;
-
-import 'dart:html';
-
 import 'package:angular2/angular2.dart';
 
 // #docregion little-tour

public/docs/_examples/user-input/dart/lib/little_tour_component.dart

@@ -1,6 +1,4 @@
 // #docregion
-library user_input.loop_back_component;
-
 import 'package:angular2/angular2.dart';
 
 // #docregion loop-back-component

public/docs/_examples/user-input/dart/lib/loop_back_component.dart

@@ -6,5 +6,5 @@ dependencies:
   browser: ^0.10.0
 transformers:
 - angular2:
-    platform_directives: 'package:angular2/src/common/directives.dart#CORE_DIRECTIVES'
+    platform_directives: 'package:angular2/common.dart#CORE_DIRECTIVES'
     entry_points: web/main.dart