Adding plugin to list all routes on a system

Provides all Linux system routing information in an array of hashes.

Example output:

```
root@ohai-plugins-vagrant:~# ohai -d /vagrant/plugins routes
[
  [
    "inet",
    [
      {
        "gateway": "10.0.2.2",
        "iface": "eth0",
        "genmask": "0.0.0.0",
        "mss": "0",
        "flags": "UG",
        "destination": "0.0.0.0",
        "window": "0",
        "irtt": "0"
      },
      {
        "gateway": "0.0.0.0",
        "iface": "eth0",
        "genmask": "255.255.255.0",
        "mss": "0",
        "flags": "U",
        "destination": "10.0.2.0",
        "window": "0",
        "irtt": "0"
      },
      {
        "gateway": "0.0.0.0",
        "iface": "eth1",
        "genmask": "255.255.255.0",
        "mss": "0",
        "flags": "U",
        "destination": "33.33.33.0",
        "window": "0",
        "irtt": "0"
      }
    ]
  ],
  [
    "inet6",
    [
      {
        "metric": "256",
        "ref": "0",
        "iface": "eth0",
        "use": "0",
        "flags": "U",
        "destination": "fe80::/64",
        "next_hop": "::"
      },
      {
        "metric": "256",
        "ref": "0",
        "iface": "eth1",
        "use": "0",
        "flags": "U",
        "destination": "fe80::/64",
        "next_hop": "::"
      },
      {
        "metric": "-1",
        "ref": "1",
        "iface": "lo",
        "use": "121",
        "flags": "!n",
        "destination": "::/0",
        "next_hop": "::"
      },
      {
        "metric": "0",
        "ref": "1",
        "iface": "lo",
        "use": "10",
        "flags": "Un",
        "destination": "::1/128",
        "next_hop": "::"
      },
      {
        "metric": "0",
        "ref": "1",
        "iface": "lo",
        "use": "0",
        "flags": "Un",
        "destination": "fe80::a00:27ff:fe5c:5eb7/128",
        "next_hop": "::"
      },
      {
        "metric": "0",
        "ref": "1",
        "iface": "lo",
        "use": "0",
        "flags": "Un",
        "destination": "fe80::a00:27ff:fe88:ca6/128",
        "next_hop": "::"
      },
      {
        "metric": "256",
        "ref": "0",
        "iface": "eth0",
        "use": "0",
        "flags": "U",
        "destination": "ff00::/8",
        "next_hop": "::"
      },
      {
        "metric": "256",
        "ref": "0",
        "iface": "eth1",
        "use": "0",
        "flags": "U",
        "destination": "ff00::/8",
        "next_hop": "::"
      },
      {
        "metric": "-1",
        "ref": "1",
        "iface": "lo",
        "use": "121",
        "flags": "!n",
        "destination": "::/0",
        "next_hop": "::"
      }
    ]
  ]
]
```