Stocks Up; Traders Eye Crude Oil Prices  NEW YORK (Reuters) - U.S. stocks made gains on Wednesday as  investors bought beaten-down shares, while strength in oil  prices pushed up energy companies such as Exxon Mobil Corp.  &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=XOM.N target=/stocks/quickinfo/fullquote"&gt;XOM.N&lt;/A&gt;