The trigger signal cannot be destroyed.

Deregister the signal formerly added.
Add a mutex system to prevent removing a signal while triggering it,
 to avoid a crash (especially if the topic was listened to).

The old names are kept for now, but will disappear in the
future.

The old names are kept for now, but will disappear in the
future.

  Launching an application in a roslaunch file may cause to send python
  command before the interpreter has read the prologue. This commit should fix
  this issue.

    RosImport entity writes data from a signal to a ROS topic.