Incorporate costmap into TEB optimization

Use our costmaps - especially the static "distance_to_obstacle_costmap" within TEB optimization.

• add a new obstacle type CostmapObstacle which is derived from teb_local_planner::Obstacle
• use bi-linear interpolation to retrieve the distance to the closest obstacle

Note: We don't need to derive geometric primitives such as described in http://wiki.ros.org/teb_local_planner/Tutorials/Costmap%20conversion

changed the description

marked the checklist item add a new obstacle type CostmapObstacle which is derived from teb_local_planner::Obstacle as completed

marked the checklist item use bi-linear interpolation to retrieve the distance to the closest obstacle as completed

mentioned in merge request !52 (merged)

closed