Strongly constrain the package versions we use. (#17)
Strongly constrain the package versions we use. (#17)

Fixes googlecartographer/cartographer_ros#271.
googlecartographer/point_cloud_viewer,cartographer-project/point_cloud_viewer,googlecartographer/point_cloud_viewer,googlecartographer/point_cloud_viewer,cartographer-project/point_cloud_viewer,cartographer-project/point_cloud_viewer,cartographer-project/point_cloud_viewer,googlecartographer/point_cloud_viewer,cartographer-project/point_cloud_viewer,googlecartographer/point_cloud_viewer