[Stackless] Bring Stackless.py in line with C based Stackless

[Andrew Francis]

Hi Folks:

I have been looking at PyPy's Stackless.py module in order to implement an 
initial prototype of stackless.select(). I'm interested see what changes would have to made in the scheduler. To this extend, I found Robert
Pike's "Implementation of Newsqueak" to be a very helpful paper.  
Eventually I will learn the PyPy tool chain and implement a language
construct.

>From what I understand, the PyPy team has not had the bandwidth to work on
Stackless.py in years. 

For the most part Stackless.py is fairly comprehensive but I see little problems in the code (i.e., I do not see a paused attribute). And now, we
have tasklet priorities. Do folks here think it is important to keep Stackless.py in line with C based Stackless?

Cheers,
Andrew