title: Error when using broom (augment) and dplyr with loess fit
body: <p>I am trying to use augment on a loess fit, but I receive the following error:</p>
  
  <pre><code>Error in data.frame(..., check.names = FALSE) : 
    arguments imply differing number of rows: 32, 11
  </code></pre>
  
  <p>In the error message, 11 happens to equal the number of observations in one segment and 32 is the total number of observations. The code is below.</p>
  
  <pre><code>require(broom)
  require(dplyr)
  
  # This example uses the lm method and it works
  regressions &lt;- mtcars %&gt;% group_by(cyl) %&gt;%  do(fit = lm(wt ~ mpg, .))
  regressions %&gt;% augment(fit)
  
  # This example uses the loess method and it generates the error
  regressions2 &lt;- mtcars %&gt;% group_by(cyl) %&gt;%  do(fit = loess(wt ~ mpg, .))
  regressions2 %&gt;% augment(fit)
  
  # The below code appropriately plots the loess fit using geom_smooth. 
  # My current # workaround is to do a global definition as an aes object in geom_smooth`
  cylc = unique(mtcars$cyl) %&gt;% sort()
  for (i in 1:length(cyl)){
    print(i)
    print(cyl[i])
    p&lt;- ggplot(data=filter(mtcars,cyl==cylc[i]),aes(x=mpg,y=wt)) + geom_point() + geom_smooth(method="loess") + ggtitle(str_c("cyl = ",cyl[i]))
    print(p)
  }
  </code></pre>