added get_velodyne_data feature
added feature for receiver the point cloud data
added feature of receivePointCloudData
added thread for receivePointCloudData
Merge pull request #24 from irvs/issue22

Issue22
comment out the feature of 3D viewer using velodyne32e
Merge pull request #25 from irvs/issue22

comment out the feature of 3D viewer using velodyne32e
Merge pull request #26 from irvs/issue21

modify thread's timing
modify sync