Added support for cylinders, spheres, cones, and generic "round"s to cram_moveit. Also, bugfixed.

Introduced the symbols and shape types mentioned above and realized reading them from the supplied object designator. A few bugs were also fixed that would result in no object being added to the collision environment after registering them. Also, a function for clearing the whole environment (on the MoveIt! side and inside cram_moveit) was introduced (`clear-collision-environment') besides the already existing function to just remove all known collision objects from the MoveIt! cache (`clear-collision-objects').