Revised RFC on range design for D2

[Andrei Alexandrescu]

In wake of the many excellent comments and suggestions made here, I made 
one more pass through the draft proposal for ranges.

http://ssli.ee.washington.edu/~aalexand/d/tmp/std_range.html

There are some comments in red illustrating some uncertainties (not 
all), and the names of the primitives have been updated. Bicycle shed 
galore! But don't forget to comment on the reactor as well :o).


Andrei