dvo_slam using gicp optimization

this code is modifed from dvo_slam

ThirdParty

• opencv 3
  follow the instructions at www.opencv.org
• pcl
  see https://github.com/PointCloudLibrary/pcl
• g2o
  see g2o
• tbb
  download the pre-build tbb package at github
• sophus 1.0
  sophus has been included in 3rdParty