Dart format with latest SDK (#63)

diff --git a/example/example.dart b/example/example.dart
index c79373f..fa73650 100644
--- a/example/example.dart
+++ b/example/example.dart
@@ -23,7 +23,9 @@
     logging = result['logging'] as bool;
     listDirectories = result['list-directories'] as bool;
   } on FormatException catch (e) {
-    stderr..writeln(e.message)..writeln(parser.usage);
+    stderr
+      ..writeln(e.message)
+      ..writeln(parser.usage);
     // http://linux.die.net/include/sysexits.h
     // #define EX_USAGE	64	/* command line usage error */
     exit(64);