Set Options to Initial Zero State
This makes sure to unset options not present in target.
Checks that options meet expectations before anything gets run
options_zero(base = merge_lists(getOption("unitizer.opts.init.base"),
getOption("unitizer.opts.init")),
as.is = union(getOption("unitizer.opts.asis.base"),
getOption("unitizer.opts.asis")))options_update(tar.opts)
validate_options(opts.to.validate, test.files = NULL)