[Rock-dev] New type to represent 3D range measurements

[Jakob Schwendner]

> > So, which types should it cover?
> > LaserScan, DistanceImage and MultilevelLaserScan? What about the sonar
> types, they are also very similar.
> Of course sonar data can be stored also in that type, but some of them may
> need some preprocessing. And it really depends on the type of sonar.
> Alex can tell more on that topic.