Added CleanupFunction to clear the GlobalService before termination

Signed-off-by: Johannes Meyer <johannes@intermodalics.eu>
Copied environment hook from rtt_ros package

This hook is only effective if RTT is installed to a catkin install space.

Signed-off-by: Johannes Meyer <johannes@intermodalics.eu>
Merge branch 'global-service-cleanup'
Merge branch 'per-package-env-hook'