Merge branch 'refs/heads/t/sqrt'

A significant speedup and a three trivial patches for int_sqrt(). No
user-visible changes. Cooking for seven weeks.

* refs/heads/t/sqrt:
  mood.c: Trivial cosmetics for int_sqrt().
  mood.c: Fix documentation of int_sqrt().
  mood: Speed up int_sqrt().
  mood: Add notice about int_sqrt().

diff --cc mood.c
Simple merge