Add echo() to module unix
Add echo() to module unix

JohnPJenkins/swift-t,swift-lang/swift-t,blue42u/swift-t,swift-lang/swift-t,swift-lang/swift-t,blue42u/swift-t,basheersubei/swift-t,blue42u/swift-t,blue42u/swift-t,basheersubei/swift-t,blue42u/swift-t,basheersubei/swift-t,swift-lang/swift-t,JohnPJenkins/swift-t,blue42u/swift-t,swift-lang/swift-t,basheersubei/swift-t,basheersubei/swift-t,basheersubei/swift-t,JohnPJenkins/swift-t,basheersubei/swift-t,JohnPJenkins/swift-t,swift-lang/swift-t,JohnPJenkins/swift-t,blue42u/swift-t,JohnPJenkins/swift-t,JohnPJenkins/swift-t,swift-lang/swift-t