Navistar Results Rise on Truck Demand  CHICAGO (Reuters) - Commercial truck maker Navistar  International Corp. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=NAV.N target=/stocks/quickinfo/fullquote"&gt;NAV.N&lt;/A&gt; said on Thursday quarterly earnings  rose as it boosted sales and controlled costs.