New features on 1.0 list

I've added two last-minute features to the 1.0 list.

http://prothon.org/wiki?pagename=OnePtZeroIndex

They are generator comprehensions and slice lists/ellipses.  Generator
comprehensions have to go in now because they replace list comprehensions.
Slice lists/ellipses are just easy.

If you have any last-minute candidates get them in now before the door
closes.

I am going to go over the Python PEP list for one last search for ideas.
Any that could easily be added in a later version will probably be put off.

I am also going to go through all the existing functions and look for list
return values that should be changed to generators.  This is also something
that can not be put off.