[Cython] Temp framework proposal

[Greg Ewing]

Dag Sverre Seljebotn wrote:

> I think it is mostly the CloneNode that scares me, that doesn't look very
> intuitive to use from a transform perspective.

On further reflection, CloneNode isn't the right thing
to use, since it assumes it's being inserted during
the analysis phase and doesn't quite do what we want.

I think the best thing would be to add a new node
type, such as LocalRefNode (and maybe rename
LocalNode to LocalDefNode to better distinguish
them).

I'm not sure I like the idea of re-using NameNode,
since it's intended to represent a name appearing
in the source code, and temp locals don't correspond
to any name in the source.

-- 
Greg