Integration to master - object collision estimator/node
Part of #687 (closed) closes #644 (closed)
Changes confined to object_collision_estimator and object_collision_estimator_node apart from ad4741e2 which contains a doc change in another module
e2fe5db6 was left out as it only changes the avp_demo launch files and cannot apply cleanly until other changes are also applied.
Edited by Liyou Zhou