Code refactoring, addition of failure handling, correction of fixed offsets
newest-designator -> current-designator

The designator shown here does not necessarily impose valid perception data and so could be (unwantedly) nullified when used in the newest-designator predicate.
Correction of fixed grasp offset poses
Extended the execution of grasp poses and simplified frame conversions
Added the `location' symbol for designator purposes
Refactored the pose planning validation function and fixed execute-move-arm-pose

The execute-move-arm-pose is temporary as the *real* underlying problem isn't clear yet.