examples/skeleton: very simple code for packet forwarding

examples/skeleton: very simple code for packet forwarding

This is a very simple example app for doing packet forwarding with the
Intel DPDK. It's designed to serve as a start point for people new to
the Intel DPDK and who want to develop a new app.

Therefore it's meant to:
* have as good a performance out-of-the-box as possible, using the
  best-known settings for configuring the PMDs, so that any new apps can
  be based off it.
* be kept as short as possible to make it easy to understand it and get
  started with it.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>