Show the total U/D ratio in the statistics tree

[SevC10]

In the statistics tree, the U/D ratio is shown only if the counters for the session are both >0. In particular, I'm referring to the function CStatTreeItemRatio::GetString() in StatTree.cpp. Would be nice to always show the total U/D ratio, regardless of the session counters.

Something like that (I'm just showing the code to better focus what I mean):

if (v1 > 0 && v2 > 0) {
    if (v2 < v1) {
        ret = CFormat(wxT("%.2f : 1")) % (v1 / v2);
    } else {
        ret = CFormat(wxT("1 : %.2f")) % (v2 / v1);
    }

    if (m_totalfunc1 && m_totalfunc2) {
        double t1 = m_totalfunc1() + v1;
        double t2 = m_totalfunc2() + v2;
        if (t2 < t1) {
            ret += CFormat(wxT(" (%.2f : 1)")) % (t1 / t2);
        } else {
            ret += CFormat(wxT(" (1 : %.2f)")) % (t2 / t1);
        }
    }
} else {
    ret = _("Not available");

    /***
    /*** Add total ratio here ***
    /***

    if (m_totalfunc1 && m_totalfunc2) {
        double t1 = m_totalfunc1() + v1;
        double t2 = m_totalfunc2() + v2;
        if (t2 < t1) {
            ret += CFormat(wxT(" (%.2f : 1)")) % (t1 / t2);
        } else {
            ret += CFormat(wxT(" (1 : %.2f)")) % (t2 / t1);
        }
    }

    /***
    /*** end modification ***
    /***
}

Screenshot (italian interface):