Revised RFC on range design for D2

[Benji Smith]

Andrei Alexandrescu wrote:
> P.S. The more I think of it, the more I like "tip" of the range. Short, 
> poignant, easy to remember. Not pressing the red button just yet.

When I see "x.tip", it makes me think of the verb ("a function that tips 
x over").

If I force myself to think of the noun-sense, "tip" is obviously at one 
of the limits of the range, but is it at the front or the back? I'd have 
to check the docs to remember.

--benji