Order to Ordering conversion #1665
Description
In #1646 there's a discussion about how there's a conversion from Order to Ordering but that it won't actually be picked up where an implicit Ordering instance is expected.
It sounds like the general consensus is that we should make it so that after you've imported cats.implicits._ you pick up this functionality.
It may not make a lot of sense to expose this as an implicit in the Order companion object, because it won't be found there during an implicit search for an Ordering instance, and having it there will probably result in ambiguous implicits if someone imports both cats.implicits._ and Order._. However, we may not want to make this incompatible change to cats-kernel. @johnynek do you have thoughts on this?