This new version mainly brings fixes to the SLAM on pose graph optimization and GPS handling and on the build and install cmake processes. 

Features available in this version : 
* Loop closure automatic detection + loading of various detections from the disk
* Failure detection and recovery mode
* Calibration estimation between 2 trajectories
* Handling of Livox sensors in ROS
* Pose graph optimization with external poses is allowed

Performances are also improved modifying the keypoints extraction and the submap extraction. The ROS interface is also improved.