title: Knitr - non-english letters
body: <p>I'm trying to create a simply pdf document using knitr package in R but I'm stuck with non-english (polish) letter. The code looks as follows:</p>
  
  <pre><code>\documentclass{article}
  
  \begin{document}
  
  \begin{center}
  \large
  \textbf{ąćółńóśźż}
  \end{center}
  
  \end{document}
  </code></pre>
  
  <p>My session info:</p>
  
  <pre><code>R version 3.1.3 (2015-03-09)
  Platform: i386-w64-mingw32/i386 (32-bit)
  Running under: Windows XP (build 2600) Service Pack 3
  
  locale:
  [1] LC_COLLATE=Polish_Poland.1250  LC_CTYPE=Polish_Poland.1250    LC_MONETARY=Polish_Poland.1250 LC_NUMERIC=C                  
  [5] LC_TIME=Polish_Poland.1250    
  
  attached base packages:
  [1] stats     graphics  grDevices utils     datasets  methods   base     
  
  other attached packages:
   [1] cairoDevice_2.22 RGtk2_2.20.31    knitr_1.10.5     plyr_1.8.3       beepr_1.2        scales_0.2.5     ggplot2_1.0.1    quantmod_0.4-5  
   [9] TTR_0.23-0       xts_0.9-7        zoo_1.7-12       RODBC_1.3-12    
  
  loaded via a namespace (and not attached):
   [1] audio_0.1-5      colorspace_1.2-6 digest_0.6.8     evaluate_0.7     formatR_1.2      grid_3.1.3       gtable_0.1.2     lattice_0.20-33 
   [9] magrittr_1.5     MASS_7.3-43      munsell_0.4.2    proto_0.3-10     Rcpp_0.12.0      reshape2_1.4.1   stringi_0.5-5    stringr_1.0.0   
  [17] tools_3.1.3   
  </code></pre>
  
  <p>I read similar topics and tried to change encoding but it doesn't work. 
  Any help would be appreciated!</p>