Investigate using openvslam for localization

[Carter90]

git clone [email protected]:xdspacelab/openvslam.git

Build from scratch? https://github.com/shinsumicco/DBoW2

From https://openvslam.readthedocs.io/en/develop/example.html#chapter-example
Or just get the file orb_vocab.dbow2
https://drive.google.com/open?id=1wUPb328th8bUqhOk-i8xllt5mgRW4n84

goal to launch via
rosrun openvslam run_slam -v ./misc/orb_vocab.dbow2 -c ./misc/camera_config.yaml -r scout_1"

Note: new flag in the yaml config file. Sync flag disabled by @Carter90 for now.

[gmfricke]

Here is a python implementation of visual slam: https://github.com/luigifreda/pyslam