cleanups in roman.g

[Jim Kingdon]

> These look good to me.

Checked in.

> The AI won't resign unless it thinks it's outnumbered 4-1 or more,
> and it only counts units it knows about, so try a test with -V on
> and/or reveal your units to the AI, see if that makes a difference.

Hmm, yeah, roman.g would be bad this way, in the sense that visibility
is set low on many units.

Setting -V doesn't really help, because that changes the ratio from
4-1 to 20-1 (see "if (side->see_all) {
       ratio /= 5;" in mplayer.c).

%reveal is probably better but I've already wasted enough time on this
testing ;-).