Simplify device network binding

This branch makes selecting an interface a little bit easier by offering the valid choices to the user if more than one interface is detected.

`--show_net` now looks like this (sorted by interface):

```bash
$ ezboot bind --show_net
Using config: /home/muffinski/ezboot.ini
Waiting for your device (is it plugged in?)
found it
192.168.1.80 (en0)
192.168.1.86 (en2)
192.168.56.1 (vboxnet0)
```

And default binding looks like this:

```bash
$ ezboot bind
Using config: /home/muffinski/ezboot.ini
Waiting for your device (is it plugged in?)
found it
1) 192.168.1.80 (en0)
2) 192.168.1.86 (en2)
3) 192.168.56.1 (vboxnet0)
Not sure which IP to use. Please select one [1]:2
About to bind host 'fireplace.local' on device to IP 192.168.1.86
remount succeeded
55 KB/s (190 bytes in 0.003s)
41 KB/s (190 bytes in 0.004s)
Great success
```

Ips starting with 127 are filtered out and if no valid options are found you should be prompted with a message asking if you're connected to a useful network.