title: Column alignment in xtable output
body: <p>I'm using <code>xtable</code> to manage <code>R</code> output in <code>Sweave</code>. See code below:</p>
  
  <pre><code>CC &lt;- data.frame(
      y = c(449, 413, 326, 409, 358, 291, 341, 278, 312)/12,
      P = ordered(gl(3, 3)), N = ordered(gl(3, 1, 9))
  )
  CC.aov &lt;- aov(y ~ N * P, data = CC , weights = rep(12, 9))
  Summary &lt;- summary(CC.aov, split = list(N = list(L = 1, Q = 2),
                                          P = list(L = 1, Q = 2)))
  Summary
  
              Df Sum Sq Mean Sq
  N            2 1016.7   508.3
    N: L       1 1012.5  1012.5
    N: Q       1    4.2     4.2
  P            2  917.4   458.7
    P: L       1  917.3   917.3
    P: Q       1    0.0     0.0
  N:P          4  399.3    99.8
    N:P: L.L   1  184.1   184.1
    N:P: Q.L   1  152.1   152.1
    N:P: L.Q   1   49.0    49.0
    N:P: Q.Q   1   14.1    14.1
  </code></pre>
  
  <p>I like to indent the first column as shown in the output above. But when I use <code>xtable(Summary)</code> the first column is aligned left. I know how to align left, right or center but could not figure out how to get the output as indented in the first. Any help in this regard will be highly appreciated. Thanks</p>