title: Strange output from fread when called from knitr
body: <p>I'm using the recently introduced <code>fread</code> function from <code>data.table</code> to read data files. 
  When I wrap my code into a knitr (Rmd) document, I noticed some strange output, namely lines like:</p>
  
  <pre><code>## 
  0%
  </code></pre>
  
  <p>even though the <code>verbose</code> option of <code>fread</code> was set to FALSE. I've used <code>sink</code> to hide this output, but I'd like to report the exact problem to the package author(s). Here's a minimal example,</p>
  
  <pre><code>library(knitr)
  
  test = "```{r}
  require(data.table) 
  fread('1 2 3\n')
  ```"
  knit2html(text=test, output="test.html")
  browseURL("test.html")
  </code></pre>
  
  <p>What is the 0% output?</p>