Allow use of NSFileHandle with print()

main.swift

var standardError = NSFileHandle.fileHandleWithStandardError()

print("hi standard error", toStream: &standardError)

NSFileHandleExtensions.swift

extension NSFileHandle: OutputStreamType {
    public func write(string: String) {
        if let data = string.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true) {
            self.writeData(data)
        }
    }
}