Min Max typo bug in xyseries.c

[jakelewis3d]

void slope_xyseries_update(SlopeXySeries *self) { SlopeXySeriesPrivate *priv = SLOPE_XYSERIES_GET_PRIVATE(self); SlopeScale * scale = slope_item_get_scale(SLOPE_ITEM(self)); const double * x = priv->x_vec; const double * y = priv->y_vec; priv->x_min = priv->x_max = x[0]; priv->y_min = priv->y_max = x[0]; //was priv->y_min = priv->y_max = y[0]; //should be long k;