Fix Actor collision if loop / auto_start false

[vvasco]

As reported here, when using the Actor Collision Plugin with this example, if loop (or auto_start) is set to false, the boxes around the actor links representing the collisions start falling around.
The problem is that in such cases, the pose of the actor is not set.
This PR proposes a fix, by setting the pose of the actor based on the last animated frame when it stops.
This is the result:

[chapulina]

Thank you for the pull request! The code looks reasonable. I'll give it a try in the coming weeks.

[chapulina]

Thanks again for the PR. Works for me!

I'm just going to trigger CI one more time to make sure all tests are ok. If you're motivated, it would be good to add a test to Actor_TEST exercising the fixed functionality.

[chapulina]

@osrf-jenkins run tests please

[vvasco]

Sure, I will add the test.

[vvasco]

I added a test to Actor_TEST, which loads the actor collision scenario with loop set to false and :

• checks that collisions are enabled;
• checks that collisions remain enabled when the actor is inactive;
• checks that links poses do not change when the actor is inactive.

[chapulina]

Thank you for adding the test! Some changes are needed for it to work on all systems, see below.

[vvasco]

I updated the new version of the test.

[chapulina]

Thank you for iterating, this is good to go!