[Cython] status update on Py3 support

[Stefan Behnel]

Hi,

Lisandro Dalcin wrote:
> - Indentifiers and (unicode) string literals can (and should) managed
> in the same table. This way, 'a.foo' will be as efficient as
> 'getattr(a, "foo")'
> 
> - Byte strings are completelly different guys, so they should be
> managed in a way similar to integer literals are.

Cython now uses one list, but keeps the information if the string was

- a unicode string
- an identifier
- decided to be interned

and then the runtime setup code 'does the right thing' depending on the
compile time environment.

Stefan