Include -xx-unset & -xx-inherit classes

[enzedonline]

There are times it is useful to apply a setting on sub-breakpoint elements but not above.
For example, to apply an order on flex items below a breakpoint but not above.
This is particularly useful on navbar menus where you might want some items to remain on the bar after collapse for example.
In this case, I would apply "order-first order-lg-unset" to the navbar-nav.
order-first moves the item before the collapsed menu so that it remains on the navbar whether or not the collapsed menu is shown
order-lg-unset removes the order-first and returns the item to its default ordering above the lg breakpoint.

Similarly for inherit
ms-2 ms-md-inherit would apply a start margin on small screens but revert to the inherited value above the md breakpoint.