robotinterface: Close as soon as one external device is closing

[traversaro]

This PR implements the idea described in #582 (comment) .

This fixes #582 .

This requires #618 to be merged before, to preview just the content of this PR before that PR is merged, check the commit 4d5ff7e .

[traversaro]

Testing on an internal model (stickBot) that was affected by this problem, with this modification we switched from the model crashing to hanging with this output:

[INFO] interrupt1 phase starting...
[INFO] interrupt1 phase finished.
[INFO] shutdown phase starting...
[INFO] Entering action level 2 of phase shutdown
[INFO] Executing detach action, level 2 on device wholebodydynamics with parameters []

I need to investigate more, but I suspect this is actually some problem of the YARP devices launched, not of the gazebo_yarp_robotinterface plugin or this modifications.

[traversaro]

Testing on an internal model (stickBot) that was affected by this problem, with this modification we switched from the model crashing to hanging with this output:

[INFO] interrupt1 phase starting...
[INFO] interrupt1 phase finished.
[INFO] shutdown phase starting...
[INFO] Entering action level 2 of phase shutdown
[INFO] Executing detach action, level 2 on device wholebodydynamics with parameters []

I need to investigate more, but I suspect this is actually some problem of the YARP devices launched, not of the gazebo_yarp_robotinterface plugin or this modifications.

Indeed, this was due to some bugs in #618 and in wholebodydynamics, once that has been fixed it was possible to respawn easily models that used gazebo_yarp_robotinterface:

stickbot_remove.mp4

[traversaro]

Thanks @Nicogene for the review. Now the history of the PR is clean.