Using run-time members in the surface modifier complicated code-review and caused an unnecessary renaming in `dna_rename_defs.h`. Also rename: - `x` -> `vert_positions_prev`. - `v` -> `vert_velocities`. - `cfra` -> `cfra_prev`.
Using run-time members in the surface modifier complicated code-review and caused an unnecessary renaming in `dna_rename_defs.h`. Also rename: - `x` -> `vert_positions_prev`. - `v` -> `vert_velocities`. - `cfra` -> `cfra_prev`.