test tool: run_mininet: support CPqD Software Switch

this patch gets run_mininet.py to support CPqD Software Switch.

usage)

  to use CPqD Software Switch:
    sudo ryu/tests/switch/run_mininet.py --switch cpqd

  to use Open vSwitch:
    sudo ryu/tests/switch/run_mininet.py --switch ovs
      or
    sudo ryu/tests/switch/run_mininet.py

Signed-off-by: Yuichi Ito <ito.yuichi0@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
ryu.app.ofctl: Add a proxy application to send OF messages

This application provides functionality similar to ofctl_rest
but via Ryu synchronous events instead of REST API.

This is intended to be used by a feature version of ryu neutron agent.

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>