Add script to verify all boilerplate; add line to make travis run it.

hack/verify-boilerplate.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+REPO_ROOT="$(realpath "$(dirname $0)/..")"
+
+result=0
+
+dirs=("pkg" "cmd")
+
+for dir in ${dirs}; do
+  for file in $(grep -r -l "" "${REPO_ROOT}/${dir}/" | grep "[.]go"); do
+    if [[ "$(${REPO_ROOT}/hooks/boilerplate.sh "${file}")" -eq "0" ]]; then
+      echo "Boilerplate header is wrong for: ${file}"
+      result=1
+    fi
+  done
+done
+
+exit ${result}