title: RMarkdown Kable width issues
body: <p>I am trying to create a table to hold some basic information using Kable in RMarkdown that will be generated in HTML, PDF, and Word. Here is the code I have</p>
  
  <pre><code>---
  title: "test"
  author: ''
  date: "2015/03/24"
  output:
   pdf_document:
   keep_tex: yes  
  ---
  
  ```{r kable1, echo=FALSE}
  Variable &lt;- c("VAR1", "VAR2", "VAR3", "VAR4")
  Label &lt;- c("LABEL", "A very       loooooooooooooooooooooooooooooooooooooooooooo     ooooooooooooooooooooooooooooooooooooooo nnnnnnngggggggg label yall", "LAB3", "LAB4")
  Classification &lt;- c("Type1", "Type2", "Type1", "Type1")
  data &lt;- data.frame(Variable, Label, Classification)
  library(knitr)
  kable(data)
  ```
  
  ```{r kable2, echo=FALSE}
  Variable &lt;- c("VAR1", "VAR2", "VAR3", "VAR4")
  Label &lt;- c("LABEL", "LabLE", "LAB3", "LAB4")
  Classification &lt;- c("Type1", "Type2", "Type1", "Type1")
  data &lt;- data.frame(Variable, Label, Classification)
  library(knitr)
  kable(data)
  ```
  </code></pre>
  
  <p>The HTML output is as follows. <img src="https://i.stack.imgur.com/m4dP4.png" alt="enter image description here">
  This is what I want. I like how the table fills out the html. However, when I produce PDF I get the following. <img src="https://i.stack.imgur.com/C2vs2.png" alt="enter image description here"></p>
  
  <p>As we can see there are issues with the PDF, the first table runs off the page and the second does not fill up the entire width. I am, unfortunately, a n00b when it comes to R, Kable, and RMarkdown. Is there a way to set options on the kable table so that the PDF looks as nice as the HTML in terms of page placement and width? Thanks!</p>