Add flipbook example

[myselfhimself]

• render images
• add effect + append_tiles with gmic-blender
• print on A4 sheets
• cut and assemble flipbook

[myselfhimself]

This depends on https://github.com/dtschump/gmic/issues/235 's fix for gmic's append_tiles command which will be in gmic 2.9.2 or so. The logic is so simple that it can be implemented in a different way for now.