SLAM-gmappig+turtlebot测试

之前测试了一下gmapping，主要是需要自己写一个launch文件。

操作系统：ubuntu14+indgo
硬件平台：turtlebot2+kinect2

<launch>
  <!-- 3D sensor -->
  <arg name="3d_sensor" default="$(env TURTLEBOT_3D_SENSOR)"/>  <!-- r200, kinect, asus_xtion_pro -->
  <include file="$(find turtlebot_bringup)/launch/3dsensor.launch">
    <arg name="rgb_processing" value="false" />
    <arg name="depth_registration" value="false" />
    <arg name="depth_processing" value="false" />
    
    <!-- We must specify an absolute topic name because if not it will be prefixed by "$(arg camera)".
         Probably is a bug in the nodelet manager: https://github.com/ros/nodelet_core/issues/7 --> 
    <arg name="scan_topic" value="/scan" />
  </include>

  <