Prefer networksetup and skip root runs

[gileswells]

Primarily I wanted to incorporate @amartignoni's simplification through networksetup over use of a private API and implement a fix for issue #28 so that I had a one stop branch that would do what I needed.

This covers both scenarios.

Closes #29

[smilinggoat]

Turns out this breaks support for SSIDs with spaces in the name. It only matches the final " lastword".

[KuuDS]

fix for SSIDs with spaces

networksetup -listallhardwareports | awk '/Wi-Fi/{getline; print $2}' | xargs networksetup -getairportnetwork | sed 's/[^:]*: //'

[smilinggoat]

fix for SSIDs with spaces

networksetup -listallhardwareports | awk '/Wi-Fi/{getline; print $2}' | xargs networksetup -getairportnetwork | sed 's/[^:]*: //'

That worked for me. Thanks!