rtt_kdl_conversions: Link to kdl_conversions instead of tf_conversions / Added new operations

With the auto-linking patch from https://github.com/orocos-toolchain/rtt/pull/20 I got some linker errors in the rtt_kdl_conversions package. The functions that this package adds RTT operations for are defined in the kdl_conversions library and tf_conversions depends on kdl_conversions. That's why I changed the dependency and link to kdl_conversions directly.

The `MsgToFrame` operation pointed to the wrong function in kdl_conversions.

The methods `TwistKDLToMsg()`, `TwistMsgToKDL()`, `PoseKDLToMsg()` and `PoseMsgToKDL()` are marked as deprecated in [kdl_msg.h](https://github.com/ros/geometry/blob/hydro-devel/kdl_conversions/include/kdl_conversions/kdl_msg.h). The second commit adds the new message names to the KDL service.