Fix for issue #86

Fix for issue #86. For simple and rmarkdown trailing white spaces were not removed in split.large.cells, so it was resulting in wrong rendering. This change only affects rendering for 'simple' and 'rmakdown' styles.

```
d> pander(col.table.transposed, style="simple", justify="right") 

------------ ----
    **blue**    2
  **orange**   13
     **red**  108
  **yellow** 1780
------------ ----

d> pander(col.table, style="simple", justify="center")


 blue   orange   red   yellow 
------ -------- ----- --------
  2       13     108    1780  
```