ReversibleCollection proposal

[Donald Raab]

> I'm also concerned about conflicts over the other method names; something like addFirst() is a pretty obvious method to add to a custom List implementation. I haven't seen any, but that doesn't mean there aren't any.
> 
> s'marks

The getFirst() and getLast() methods will have collisions. We have both these methods on Eclipse Collections, and thankfully they return the same type. It is possible that someone decided to implement these methods and return Optional.