[freeciv-ai] CM and celebration

[Benoit Hudson <bh@xxxxxxxxxxxxxxxxxxx>]

When you put a high premium on celebration in the CMA (which for me is
always), cities of size 2 will often use one citizen as an entertainer
and thus have 1 happy and 1 entertainer, which is a majority of happy.
But cities of size 2 can't be in celebration (at least in the default
ruleset).

What's the correct way to deal with this issue?  None of the functions
in city.c address that.  "city_happy", which is what we call, just
checks for a majority of citizens being happy (regardless of number).
"city_celebrating" checks for size, but also requires that the city have
been happy the turn before, which we don't want.

        -- Benoît