x/mobile/example: paint event sending is too much on iOS

[nobonobo]

• Go 1.5.2(OS-X 10.10)
• target device: iPhone5s iOS 9.1
• expected behavior: Just a good paint frequency.
• instead behavior: high CPU load and Irregular paint timing.

iOS device requires following patch

diff --git a/example/basic/main.go b/example/basic/main.go
index 2b2e0c9..f826c45 100644
--- a/example/basic/main.go
+++ b/example/basic/main.go
@@ -89,7 +89,7 @@ func main() {
                                a.Publish()
                                // Drive the animation by preparing to paint the next frame
                                // after this one is shown.
-                               a.Send(paint.Event{})
+                               //a.Send(paint.Event{})
                        case touch.Event:
                                touchX = e.X
                                touchY = e.Y

[nobonobo]

But, this statement is required for Android:

a.Send(paint.Event{})

[rakyll]

/cc @crawshaw