swift scripting for 2.2 and 3.0!

echo_2_2.swift

#!/usr/bin/env xcrun swift

let arguments = Array(Process.arguments.dropFirst())
print(arguments.joinWithSeparator(","))

echo_3_0.swift

#!/usr/bin/env xcrun swift

let arguments = Array(CommandLine.arguments.dropFirst())
print(arguments.joined(separator: ","))