Add pubspec.yaml files for each of the examples/ directories

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
@@ skipping 113 matching lines @@
 
 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.
+Sky applications inside the `SkyDemo.apk` harness.  The sky_tool script expects
+to be run from the root directory of your application pub package.  To run
+one of the examples in this SDK, try:
 
-1. ``packages/sky/sky_tool start --install examples/stocks/main.sky``
+1. ``cd examples/stocks``
+
+2. ``pub get`` to set up a copy of the sky package in the app directory.
+
+3. ``./packages/sky/sky_tool start --install``
    The --install flag is only necessary to install SkyDemo.apk if not already
-   installed from the Google Play store.
+   installed on the device.
 
-2.  Use ``adb logcat`` to view any errors or Dart print() output from the app.
+4. Use ``adb logcat`` to view any errors or Dart print() output from the app.
+   ``adb logcat -s chromium`` can be used to filter only adb messages from
+   `SkyDemo.apk` (which for
+   [legacy reasons](https://github.com/domokit/mojo/issues/129) still uses the
+   android log tag 'chromium').
 
 Measuring Performance
 ---------------------
 
 Sky has support for generating trace files compatible with
 [Chrome's about:tracing](https://www.chromium.org/developers/how-tos/trace-event-profiling-tool).
 
 `packages/sky/sky_tool start_tracing` and `packages/sky/sky_tool stop_tracing`
 are the commands to use.
 
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 [Keyboard](https://github.com/domokit/mojo/blob/master/mojo/services/keyboard/public/interfaces/keyboard.mojom)
 service to allow Sky Framework Dart code to interface with the underlying
 platform's Keyboard, but also to expose any additional non-Dart business logic
 to Sky/Dart UI code.
 
 As and example, [SkyApplication](https://github.com/domokit/mojo/blob/master/sky/shell/org/domokit/sky/shell/SkyApplication.java)
 exposes a mojo `network_service` (required by Sky Engine C++ code)
 [SkyDemoApplication](https://github.com/domokit/mojo/blob/master/sky/apk/demo/org/domokit/sky/demo/SkyDemoApplication.java)
 additionally exposes `keyboard_service` and `sensor_service` for use by the Sky
 Framework from Dart.