Move example out of sky/packages to //examples

examples/README.md

@@ -0,0 +1,16 @@
+Sky Examples
+============
+
+This directory contains several examples of using Sky.  Each of these is an
+individual Dart application package.  If you wish to run them with `sky_tool`
+then you will want to run `pub get` inside their directory before running
+`./packages/sky/sky_tool start`.
+
+1. *Hello, world.* The [hello world app](hello_world) is a basic app that shows
+   the text "hello, world."
+
+2. *Stocks.* The [stocks app](stocks) is an example of a typical mobile app
+   built using Sky. The app shows a list of all the stocks in the NASDAQ.
+
+3. *Widgets.* The [widgets app](widgets) contains a number of Sky widgets so
+   you can experiment with them in a simple container.