Improve run-example.sh

- More usage example
- Newlines for prettier output

run-example.sh

@@ -28,11 +28,14 @@ done
 if [[ -z "$EXAMPLE" ]] || [[ -z "$EXAMPLE_CLASS" ]] || [[ $# -ne 0 ]]; then
   echo "  Usage: $0 [-D<name>[=<value>] ...] <example-name>" >&2
   echo "Example: $0 -Dport=8443 -Dssl http-server" >&2
+  echo "         $0 -Dhost=127.0.0.1 -Dport=8009 echo-client" >&2
   echo >&2
   echo "Available examples:" >&2
+  echo >&2
   for E in "${!EXAMPLE_MAP[@]}"; do
     echo "  $E"
   done | sort >&2
+  echo >&2
   exit 1
 fi