Indigo devel sync

This syncs via cherry-pick all my recent changes from hydro to indigo

Note still has pending PRs in it from hydro (please merge my hydro PRs):
https://github.com/ros-planning/moveit_core/pull/177
https://github.com/ros-planning/moveit_core/pull/180
https://github.com/ros-planning/moveit_core/pull/182