Attribute Order Shouldn't Matter

[brodieG]

Currently, if more than one attribute is missing or wrong, which attribute is reported as problematic depends on the order the attribute shows up in the attribute pair list.

    > Recent bug fixes in the development version of R,
    > "R-devel",   (see the short thread starting here:  
    > https://stat.ethz.ch/pipermail/r-devel/2018-March/075644.html
    > ) have lead your packages to no longer pass  'R CMD
    > check'  with that version of R-devel:

    >  https://www.r-project.org/web/checks/check_results_nima.html
    > https://www.r-project.org/web/checks/check_results_vetr.html

    > In both cases, the reason is a *too strict* test, you not
    > only check that the attributes (of a certain data frame)
    > are correct, but you *wrongly* also check that the list
    > which attributes(<df>) returns has the attributes in a
    > given order.

    > Instead please fix your check e.g., to use identical() if
    > appropriate, because even identical() with its default
    > argument 'attr.as.set = TRUE'  does *not* distinguish
    > objects where only the attributes are re-ordered.

    > Best regards,

    > Martin Maechler ETH Zurich  and  R Core Team