squash merge from dev branch

vendor/gopkg.in/alecthomas/kingpin.v2/_examples/ping/main.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"fmt"
+
+	"gopkg.in/alecthomas/kingpin.v2"
+)
+
+var (
+	debug   = kingpin.Flag("debug", "Enable debug mode.").Bool()
+	timeout = kingpin.Flag("timeout", "Timeout waiting for ping.").OverrideDefaultFromEnvar("PING_TIMEOUT").Required().Short('t').Duration()
+	ip      = kingpin.Arg("ip", "IP address to ping.").Required().IP()
+	count   = kingpin.Arg("count", "Number of packets to send").Int()
+)
+
+func main() {
+	kingpin.Version("0.0.1")
+	kingpin.Parse()
+	fmt.Printf("Would ping: %s with timeout %s and count %d", *ip, *timeout, *count)
+}