fix #342 mqtt password is hidden now

tools/esp8266/html/setup.html

@@ -82,7 +82,7 @@
                         <label for="mqttUser">Username (optional)</label>
                         <input type="text" class="text" name="mqttUser"/>
                         <label for="mqttPwd">Password (optional)</label>
-                        <input type="text" class="text" name="mqttPwd"/>
+                        <input type="password" class="text" name="mqttPwd"/>
                         <label for="mqttTopic">Topic</label>
                         <input type="text" class="text" name="mqttTopic"/>
                     </fieldset>