Fix quoting of default variable in template (#91)

* Revert "don't quote reveal options in template". This reverts commit 633c05f47dca23c48382804bd8d0cf9d55d018bb fixing #72 
* Only quote specific option that can be character or else like slideNumber https://revealjs.com/slide-numbers/
diff --git a/DESCRIPTION b/DESCRIPTION
index 7f82218..30f5a45 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: revealjs
 Type: Package
 Title: R Markdown Format for 'reveal.js' Presentations
-Version: 0.9
+Version: 0.9.1
 Date: 2017-03-13
 Authors@R: c(
     person("Hakim", "El Hattab", role = c("aut", "cph"),