* new/remove for GPencil frames/strokes/ * add/pop for points * clear for frame/layer & grease_pencil * copy for frame + fix for free_gpencil_frames() not clearing the active frame
* new/remove for GPencil frames/strokes/ * add/pop for points * clear for frame/layer & grease_pencil * copy for frame + fix for free_gpencil_frames() not clearing the active frame