title: Rselenium makeFirefoxProfile not implemented
body: <p>I am trying to run a RSelenium instance to download some pdf files for me without having to click on the dialog boxes (or it opening using pdfjs). </p>
  
  <p>But even if I set my configurations, the Firefox instance still loads the default profile. </p>
  
  <p>RSelenium version: <code>1.73</code></p>
  
  <p>Firefox version: <code>56.0 (32-bit)</code></p>
  
  <p>Windows: <code>7 Ultimate</code> </p>
  
  <p>Create profile and start server:</p>
  
  <pre><code>library(RSelenium)
  library(rvest)
  library(XML)
  library(stringi)
  
  cprof &lt;- makeFirefoxProfile(list(
    pdfjs.disabled = TRUE,
    plugin.scan.plid.all = FALSE,
    plugin.scan.Acrobat = "99.0",
    browser.helperApps.neverAsk.saveToDisk = 'application/pdf',
    browser.download.dir = "C:\\temp")
  )
  
  remDr &lt;- rsDriver(port = 4477L, browser = "firefox", check = FALSE, extraCapabilities = cprof)
  
  remDr &lt;- remDr[["client"]]
  </code></pre>
  
  <p>After Firefox launches I check the configs, the settings have remained in their default state:
  <a href="https://i.stack.imgur.com/TivD9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/TivD9.png" alt="enter image description here"></a></p>