content/h2push: initial commit of the example server

Change-Id: I500f049e5855d008fd8185603033f72a3fd39b4f
Reviewed-on: https://go-review.googlesource.com/38428
Reviewed-by: Tom Bergan <tombergan@google.com>
Run-TryBot: Tom Bergan <tombergan@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
5 files changed