Remove smart argument as it is no more present in `html_document_base()`

Following https://github.com/rstudio/rmarkdown/issues/1774 as Pandoc sets it by default.

Closes #107
diff --git a/R/revealjs_presentation.R b/R/revealjs_presentation.R
index 542df58..12edafc 100644
--- a/R/revealjs_presentation.R
+++ b/R/revealjs_presentation.R
@@ -6,9 +6,6 @@
 #' @inheritParams rmarkdown::pdf_document
 #' @inheritParams rmarkdown::html_document
 #'
-#' @param smart Produce typographically correct output, converting straight
-#'  quotes to curly quotes, \code{---} to em-dashes, \code{--} to en-dashes, and
-#'  \code{...} to ellipses.
 #' @param center \code{TRUE} to vertically center content on slides
 #' @param slide_level Level of heading to denote individual slides. If
 #'   \code{slide_level} is 2 (the default), a two-dimensional layout will be
@@ -71,7 +68,6 @@
                                   fig_height = 6,
                                   fig_retina = if (!fig_caption) 2,
                                   fig_caption = FALSE,
-                                  smart = TRUE,
                                   self_contained = TRUE,
                                   theme = "simple",
                                   transition = "default",
@@ -243,7 +239,7 @@
     clean_supporting = self_contained,
     pre_processor = pre_processor,
     base_format = html_document_base(
-      smart = smart, lib_dir = lib_dir,
+      lib_dir = lib_dir,
       self_contained = self_contained,
       mathjax = mathjax,
       pandoc_args = pandoc_args,
diff --git a/README.Rmd b/README.Rmd
index a78d115..b9ec1bc 100644
--- a/README.Rmd
+++ b/README.Rmd
@@ -128,8 +128,6 @@
 
 * `center` specifies whether you want to vertically center content on slides (this defaults to false).
 
-* `smart` indicates whether to produce typographically correct output, converting straight quotes to curly quotes, `---` to em-dashes, `--` to en-dashes, and `...` to ellipses. Note that `smart` is enabled by default.
-
 For example:
 
     ---
diff --git a/README.md b/README.md
index 913abdd..a315d62 100644
--- a/README.md
+++ b/README.md
@@ -146,11 +146,6 @@
 -   `center` specifies whether you want to vertically center content on
     slides (this defaults to false).
 
--   `smart` indicates whether to produce typographically correct output,
-    converting straight quotes to curly quotes, `---` to em-dashes, `--`
-    to en-dashes, and `...` to ellipses. Note that `smart` is enabled by
-    default.
-
 For example:
 
     ---
diff --git a/man/revealjs_presentation.Rd b/man/revealjs_presentation.Rd
index d9b4a00..e89753d 100644
--- a/man/revealjs_presentation.Rd
+++ b/man/revealjs_presentation.Rd
@@ -12,7 +12,6 @@
   fig_height = 6,
   fig_retina = if (!fig_caption) 2,
   fig_caption = FALSE,
-  smart = TRUE,
   self_contained = TRUE,
   theme = "simple",
   transition = "default",
@@ -58,10 +57,6 @@
 
 \item{fig_caption}{\code{TRUE} to render figures with captions}
 
-\item{smart}{Produce typographically correct output, converting straight
-quotes to curly quotes, \code{---} to em-dashes, \code{--} to en-dashes, and
-\code{...} to ellipses.}
-
 \item{self_contained}{Whether to generate a full LaTeX document (\code{TRUE})
 or just the body of a LaTeX document (\code{FALSE}). Note the LaTeX
 document is an intermediate file unless \code{keep_tex = TRUE}.}
@@ -153,5 +148,4 @@
 render("pres.Rmd", revealjs_presentation(incremental = TRUE))
 }
 
-
 }