add a flutter.yaml file for the widgets project

examples/widgets/README → examples/widgets/README.md

 Small examples of the Flutter widget framework
 ==============================================
 
-To run these, open a terminal in this directory and use the following
-command:
+To run these, open a terminal in this directory and use the following command:
 
 ```bash
-pub global activate flutter
 flutter start --checked -t foo.dart
 ```
 

examples/widgets/flutter.yaml

+name: widgets
+material-design-icons:
+  - name: action/account_circle
+  - name: action/alarm
+  - name: action/android
+  - name: action/assessment
+  - name: action/code
+  - name: action/event
+  - name: action/face
+  - name: action/home
+  - name: action/language
+  - name: action/list
+  - name: device/dvr
+  - name: editor/format_align_center
+  - name: editor/format_align_left
+  - name: editor/format_align_right
+  - name: navigation/arrow_back
+  - name: navigation/arrow_forward
+  - name: navigation/menu
+  - name: navigation/more_horiz
+  - name: navigation/more_vert
+  - name: navigation/refresh