This is a modified version of ORB-SLAM2. For the original description please see this.
17 Feb 2020: Replaced g2o with the newest version, which now works well with Eigen3 3.3.6 and higher. Previously there was a problem when building with Eigen3 version higher than 3.3.2 would give your tons of warnings, because of a deprecated flag. However, this build is not fully tested, so it might broke when working with older versions. Also solved the issue of not being able to find usleep, by adding the header <unistd.h> to System.h.