Sync melodic-devel to moveit2/master

[davetcoleman]

We're only 2 commits behind, but i wanted to test the waters now. How I did this:

git clone git@github.com:ros-planning/moveit
git remote add davetcoleman2 git@github.com:davetcoleman/moveit2
git push davetcoleman2 melodic-devel

This allows my fork of moveit2 to have the latest melodic-devel branch. Then using Github's interface I created a PR from melodic-devel to master

EDIT [rhaschke]:
The proposed approach seems to generate extra merge commits as seen in #35.
A better sync approach is described in #36.

[rhaschke]

It will be important to merge commit such syncs, otherwise commit history is screwed up.