include xcolor in save_kable
diff --git a/R/save_kable.R b/R/save_kable.R
index 8238552..2f91fd4 100644
--- a/R/save_kable.R
+++ b/R/save_kable.R
@@ -130,6 +130,7 @@
     latex_pkg_list(),
     "\\usepackage{graphicx}",
     "\\usepackage{xltxtra,xunicode}",
+    "\\usepackage{xcolor}",
     latex_header_includes,
     "\\begin{document}",
     solve_enc(x),