title: How is a unique id being added to my (python) Splinter screenshot filenames?
body: <p>I'm using Splinter (in Chrome browser) to take screenshots of website pages. I am naming the files exactly as I want them but unique strings are being added to the end of my filenames (eg, "filename2k3j39.png"). I haven't found anything in the Splinter or Selenium documentation that indicates that these are added. What part of the program is adding the Unique Ids? Windows 10, Chromedriver, Selenium, Splinter? </p>
  
  <p>I've checked my Chrome settings and don't see anything. Files are saved as a PNG so it's not a PDF setting. </p>
  
  <pre><code>from splinter import Browser
  executable_path = {'executable_path':r'C:\Users\me\chromedriver.exe'}
  browser = Browser('chrome', **executable_path)
  
  screenshot_path = browser.screenshot('C:/Home/Progress/me/screen shots/' + my_var + '/web/www_' + name + ' (' + now.strftime("%Y-%m-%d") + ')', full=True)
  </code></pre>
  
  <p>The result is <code>www_Name (1-1-2000)2k3j39.png</code> instead of <code>www_Name (1-1-2000).png</code></p>