da8f16e288
So far, we had an operator to 'bake' keyframe curves into samples, but no way to make the fcurve editable again (i.e. to convert it back into a keyframes one). Needed to fix mocap addon (see T43259). Also, fixed a glitch in `fcurve_store_samples()`, since given end frame is included in range, it is valid to give same start and end frame (in case you want a single point in samples, not much practical cases, but...).