Removed problematic dependency

When depending on moveit_msgs-srv, the system reports it cannot find moveit_msgs-msg. This might be due to a missing dependency in moveit_msgs-srv to moveit_msgs-msg. The problematic dependency is removed here as we don't use ROS services but only actionlib services.
Added a specific failure for being unable to transform into a given link
Extended attaching and detaching objects to links

Attaching and detaching objects to and from links respectively now works. The current pose of the object to be attached/detached is taken into account and is positioned relative to the link it is to be attached to.
This can be refined by reading the current collision object's pose from the planning server (and therefore, the user does not have to specify the pose every time).
Added functions for copying the *real* robot state into the planning scene robot

Also, for that purpose, implemented an interface to use the joint-states function from outside of cram_moveit (the function returns a list of all joints as currently being advertised via /joint_states).
Exported new function signatures accordingly