Rename fletch -> dartino

pkg/mqtt/publish-sample.dart

-import 'dart:fletch';
+import 'dart:dartino';
 import 'package:mqtt/mqtt.dart';
 
 // Sample code for publishing messages.
 //
 // For an end-to-end sample, first run subscribe-sample.dart, and then start
 // this program next to see the communication between the two. Note that this
-// program has to be started in a second session, e.g. `fletch start
+// program has to be started in a second session, e.g. `dartino start
 // publish-sample.dart in session 2'.
 void main() {
   // Create MQTT client.
   Client c = new Client('tcp://test.mosquitto.org:1883', 'test123-client1',
     protocolVersion: 3);
 
   // Publish some messages.
   for (int i = 1; i <= 3; i++) {
     c.publish('Message $i', '/foo/bar');
     c.publish('Message $i', '/foo/baz');
   }
 
   // Clean up.
   c.disconnect();
 }