title: Make R Markdown table borders visible after kniting to .doc
body: <p>I have table defined like that</p>
  
  <pre><code>```{r results='asis'}
  library(Ryacas)
  library(pander)
  m&lt;-rbind(c("x","x^2"),c("y","y^2"))
  Apycs&lt;-function(m){
    library(Ryacas)
    m1&lt;-m 
    for (k in 1:nrow(m)){ for (l in 1:ncol(m)){
      m.2&lt;-yacas(TeXForm(m[k,l]))[[2]]
      m1[k,l]&lt;-substr(m.2,2,nchar(m.2)-2)}}
    return(m1)}
  m&lt;-Apycs(m)
  pandoc.table(m, style="grid")
  
  ```
  </code></pre>
  
  <p>How to make lines that separate table cells visible  (print preview in .doc) <br/> file without doing it manually ?</p>