Added utility functions for ensurance of pose transformation

These functions were formerly part of cram_moveit, but turned out to be non-moveit-specific. As they are used in other packages, they are moved to cl-tf2 to not introduce unnecessary dependencies towards cram_bridge (which contains cram_moveit).
Okay, doc strings are added for all the utility functions in https://github.com/fairlight1337/roslisp_common/commit/a3848eb8765e6069e8731e3ae316e519f99921c9.

Also, a function was doubling another functions funtionality (and wasn't actually used anywhere). That's fixed as well.