title: rmarkdown beamer presentation: how to not print section slides?
body: <p>I am writing a beamer presentation in rmarkdown and converting it to pdf with knitr. I want to define sections at the header1 level, e.g. <code># Introduction</code>, and then have a slide titled something else e.g. <code>## Introducing my brilliant research</code>. Having the header1 level define sections is nice as the names of the sections can be displayed in the slide header in certain beamer themes, and this is why I include it. </p>
  
  <p>But I do not want rmarkdown to insert a slide that simply says the name of the section between sections, which at the moment it is doing. Is there a way to not print a slide with the section name between sections? I thought <code>slide_level</code> would control this behavior but it does not seem to (or perhaps I am using it wrong).</p>
  
  <p>A minimal reproducible example of my problem can be obtained with this code:</p>
  
  <pre><code>---
  title: "Test Pres"
  author: "Professor Genius Researcher"
  date: "24 February 2017"
  output: 
    beamer_presentation:
      slide_level: 2
      theme: "Singapore"
      colortheme: "rose"
  ---
  
  ```{r setup, include=FALSE}
  knitr::opts_chunk$set(echo = FALSE)
  ```
  
  # Markdown Intro
  
  ## R Markdown
  
  This is an R Markdown presentation. Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents. For more details on using R Markdown see &lt;http://rmarkdown.rstudio.com&gt;.
  
  When you click the **Knit** button a document will be generated that includes both content as well as the output of any embedded R code chunks within the document.
  
  # Using Bullets
  
  ## Slide with Bullets
  
  - Bullet 1
  - Bullet 2
  - Bullet 3
  
  # Including Chunks
  
  ## Slide with R Output
  
  ```{r cars, echo = TRUE}
  summary(cars)
  ```
  
  ## Slide with Plot
  
  ```{r pressure}
  plot(pressure)
  ```
  </code></pre>
  
  <p>At the moment, this code produces slides that say Markdown Intro, Using Bullets, and Including Chunks. I would like those slides labeling the sections omitted. Is this possible?</p>