Two features requested by animators:
* Copy Visual Pose: a combination of existing functionality to copy visual poses between bones and copy pose that works between frames.
* Paste Pose over frame range: when pasting a pose, it can be useful to paste it over a specified range of frames.
Both of these features can be done in a relatively simple way, however in general with rigs just copying and pasting the matrix after constraints and parenting are applied does not necessarily lead to the same resulting pose. At least parenting should be taken into account intelligently (pasting in order from parent to child), for constraints or IK it may be very hard to do well.