Merge pull request #1523 from demoneaux/readme-fix

Make PDF export section less OS X specific.

README.md

@@ -732,7 +732,7 @@ Presentations can be exported to PDF via a special print stylesheet. This featur
 Here's an example of an exported presentation that's been uploaded to SlideShare: http://www.slideshare.net/hakimel/revealjs-300.
 
 1. Open your presentation with `print-pdf` included anywhere in the query string. This triggers the default index HTML to load the PDF print stylesheet ([css/print/pdf.css](https://github.com/hakimel/reveal.js/blob/master/css/print/pdf.css)). You can test this with [lab.hakim.se/reveal-js?print-pdf](http://lab.hakim.se/reveal-js?print-pdf).
-2. Open the in-browser print dialog (CMD+P).
+2. Open the in-browser print dialog (CTRL/CMD+P).
 3. Change the **Destination** setting to **Save as PDF**.
 4. Change the **Layout** to **Landscape**.
 5. Change the **Margins** to **None**.