Update two-processes talk example

I also felt a need to describe why is there a receive function (what should we notice about it).
Set fill-column to 80

Instead of emacs's default 70.
Switch places of handlers

To correspond docs that follow.
Remove unused function and redundant do
Cosmetic (and we don't need to print when replying)
Cosmetic (ish) tweaks
Merge branch k-bx:patch-3 - thanks Konstantine Rybnikov