Could `-N` / `--new-start` be given an alias, like `--clobber` or `--overwrite`?

[vreuter]

I find the alternatives suggested in the title a bit more intuitive, especially if suffixed with something like -existing or -existing-results or -preveious-results, etc.

@nsheff @donaldcampbelljr @khoroshevskyi @nleroy917