refactor PNode/BoxNode protocol impls, rename seed -> seed-box, update various operator impls, add new helpers: reflect-seq, inject, sphere-lat, switch union-mesh to use to BasicMesh by default, refactor walk fn
refactor PNode/BoxNode protocol impls, rename seed -> seed-box, update various operator impls, add new helpers: reflect-seq, inject, sphere-lat, switch union-mesh to use to BasicMesh by default, refactor walk fn

thi-ng/morphogen