Add hack/update-godep-licenses.sh to generate Godeps/LICENSES.md

- Add Godeps/LICENSES.md
- Add verify-godep-licenses to verify that Godeps/LICENSES.md is up to date
- Trigger verify-godep-licenses in the pre-commit hook only if the Godeps dir has changed
- Exclude verify-godep-licenses in verify-all
- Add verify-godep-licenses to make verify (used by travis)
- Add verify-godep-licenses to shippable
- Update dev docs to mention update-godep-licenses

hooks/pre-commit

@@ -28,6 +28,16 @@ if [[ "${#files[@]}" -ne 0 ]]; then
     echo "${green}OK"
   fi
   echo "${reset}"
+
+  echo -ne "Check if Godep licesnses are up to date..."
+  if ! OUT=$("hack/verify-godep-licenses.sh" 2>&1); then
+    echo
+    echo "${red}${OUT}"
+    exit_code=1
+  else
+    echo "${green}OK"
+  fi
+  echo "${reset}"
 fi
 
 echo -ne "Checking for files that need gofmt... "