Update sky/sdk/README.md instructions

sky/sdk/README.md

 Sky
 ===
 
 Sky is an experimental, high-performance UI framework for mobile apps. Sky helps
 you create apps with beautiful user interfaces and high-quality interactive
 design that run smoothly at 120 Hz.
 
 Sky consists of two components:
 
 1. *The Sky engine.* The engine is the core of the system. Written in C++, the
    engine provides the muscle of the Sky system. The engine provides
    several primitives, including a soft real-time scheduler and a hierarchial,
    retained-mode graphics system, that let you build high-quality apps.
 
 2. *The Sky framework.* The [framework](packages/sky/lib/framework) makes it
    easy to build apps using Sky by providing familiar user interface widgets,
    such as buttons, infinite lists, and animations, on top of the engine using
    Dart. These extensible components follow a functional programming style
    inspired by [React](http://facebook.github.io/react/).
 
 We're still iterating on Sky heavily, which means the framework and underlying
 engine are both likely to change in incompatible ways several times, but if
 you're interested in trying out the system, this document can help you get
 started.
 
 Examples
 --------
 
-The simplest Sky app is, appropriately, HelloWorldApp:
+Sky uses Dart and Sky applications are
+[Dart Packages](https://www.dartlang.org/docs/tutorials/shared-pkgs/).
+Application creation starts by creating a new directory and
+adding a [pubspec.yaml](https://www.dartlang.org/tools/pub/pubspec.html):
+
+ pubspec.yaml for your app:
+```yaml
+name: your_app_name
+dependencies:
+ sky: any
+```
+
+Once the pubspec is in place, create a `lib` directory (where your dart code
+will go) and run `pub get` to download all necessary dependencies and create
+the symlinks necessary for 'package:your_app_names/main.dart' includes to work.
+
+Currently the Sky Engine assumes the entry point for your application is a
+`main` function is located inside a `main.sky` file at the root of the package.
+`.sky` is an html-like format:
+```
+<sky>
+<script>
+import 'package:your_app_name/main.dart'
+
+void main() {
+  new HelloWorldApp();
+}
+</script>
+</sky>
+```
+
+The rest of the application then goes inside the `lib` directory of the package
+thus `lib/main.dart` would be:
 
 ```dart
 import 'package:sky/framework/fn.dart';
 
 class HelloWorldApp extends App {
   UINode build() {
     return new Text('Hello, world!');
   }
 }
-
-void main() {
-  new HelloWorldApp();
-}
 ```
 
 Execution starts in `main`, which creates the `HelloWorldApp`. The framework
 then marks `HelloWorldApp` as dirty, which schedules it to build during the next
 animation frame. Each animation frame, the framework calls `build` on all the
-dirty components and diffs the virtual `UINode` hierarchy returned this frame with
-the hierarchy returned last frame. Any differences are then applied as mutations
-to the physical hierarchy retained by the engine.
+dirty components and diffs the virtual `UINode` hierarchy returned this frame
+with the hierarchy returned last frame. Any differences are then applied as
+mutations to the physical hierarchy retained by the engine.
 
-For more examples, please see the [examples directory](examples/).
+For examples, please see the [examples directory](examples/).
 
 Services
 --------
 
-Sky apps can access services from the host operating system using Mojo. For
+Sky apps can access services from the host operating system using Mojo IPC. For
 example, you can access the network using the `network_service.mojom` interface.
 Although you can use these low-level interfaces directly, you might prefer to
 access these services via libraries in the framework. For example, the
 `fetch.dart` library wraps the underlying `network_service.mojom` in an
 ergonomic interface:
 
 ```dart
 import 'package:sky/framework/net/fetch.dart';
 
 main() async {
-  var response = await fetch('example.txt');
+  Response response = await fetch('example.txt');
   print(response.bodyAsString());
 }
 ```
 
 Set up your computer
 --------------------
 
 1. Install the Dart SDK:
   - https://www.dartlang.org/tools/download.html
 
@@ skipping 16 matching lines @@
    and tapping the ``Build number`` field five times.
 
 2. Enable ``USB debugging`` in ``Settings > Developer options``.
 
 3. Using a USB cable, plug your phone into your computer. If prompted on your
    device, authorize your computer to access your device.
 
 Running a Sky application
 -------------------------
 
+The `sky` pub package includes a `sky_tool` script to assist in running
+Sky applications inside the `SkyDemo.apk` harness.
+
 1. ``packages/sky/lib/sky_tool --install examples/stocks/main.sky``

[Matt Perry, 2015/04/27 21:32:27]

This didn't work for me. I get this error:
usage: sky_tool [-h] {start,stop} ...
sky_tool: error: invalid choice: 'examples/stocks/main.sky' (choose from
'start', 'stop')

I get further (but I still hit errors) if I run this:
Serving HTTP on 0.0.0.0 port 9888 ...
Starting: Intent { act=android.intent.action.VIEW
dat=sky://localhost:9888/main.sky }
127.0.0.1 - - [27/Apr/2015 17:30:36] "GET /main.sky HTTP/1.1" 200 -
127.0.0.1 - - [27/Apr/2015 17:30:36] "GET /lib/stock_app.dart HTTP/1.1" 200 -
127.0.0.1 - - [27/Apr/2015 17:30:36] code 404, message File not found
127.0.0.1 - - [27/Apr/2015 17:30:36] "GET
/packages/sky/framework/components/action_bar.dart HTTP/1.1" 404 -
127.0.0.1 - - [27/Apr/2015 17:30:36] code 404, message File not found
127.0.0.1 - - [27/Apr/2015 17:30:36] "GET
/packages/sky/framework/components/drawer.dart HTTP/1.1" 404 -
127.0.0.1 - - [27/Apr/2015 17:30:37] code 404, message File not found
127.0.0.1 - - [27/Apr/2015 17:30:37] "GET
/packages/sky/framework/components/drawer_header.dart HTTP/1.1" 404 -
127.0.0.1 - - [27/Apr/2015 17:30:37] code 404, message File not found
127.0.0.1 - - [27/Apr/2015 17:30:37] "GET
/packages/sky/framework/components/floating_action_button.dart HTTP/1.1" 404 -
127.0.0.1 - - [27/Apr/2015 17:30:37] code 404, message File not found
127.0.0.1 - - [27/Apr/2015 17:30:37] "GET
/packages/sky/framework/components/action_bar.dart HTTP/1.1" 404 -
127.0.0.1 - - [27/Apr/2015 17:30:37] code 404, message File not found
127.0.0.1 - - [27/Apr/2015 17:30:37] "GET
/packages/sky/framework/components/drawer.dart HTTP/1.1" 404 -

-   The --install flag is only necessary the first time to install SkyDemo.apk.
+   The --install flag is only necessary to install SkyDemo.apk if not already
+   installed from the Google Play store.
 
 2.  Use ``adb logcat`` to view any errors or Dart print() output from the app.
+
+Building a standalone MyApp
+---------------------------
+
+Although it is possible to bundle the Sky Engine in your own app (instead of
+running your code inside SkyDemo.apk), right now doing so is difficult.
+
+There is one example of doing so if you're feeling brave:
+https://github.com/domokit/mojo/tree/master/sky/apk/stocks
+
+Eventually we plan to make this much easier and support platforms other than
+Android, but that work is yet in progress.