Issue #88: put depthimage_to_laserscan on camera ns.
This doesn't fix the problem, really, but makes it explicit.
To fix (temporally, until we really understand the problem) we must get
an absolute topic name for scan
Issue #82: resolve namespace conflict. Now it can resolve multiple
robots environment problem
Merge branch 'hydro-devel' of https://github.com/turtlebot/turtlebot into hydro-devel