Using consistent date format

UserManual.md

@@ -15,10 +15,10 @@ Embedding
 
 Other Resources
 ---------------
-- A presentation made by Arnout Vandecappelle at FOSDEM 2011 on 2011/02/06
+- Presentation made by Arnout Vandecappelle at FOSDEM 2011 on 2011-02-06
   in Brussels, Belgium, called
   "Creating secure web based user interfaces for Embedded Devices"
   ([pdf](http://mind.be/content/110206_Web-ui.pdf) |
    [odp](http://mind.be/content/110206_Web-ui.odp))
-- A Linux Journal article by Michel J.Hammel, 2010-04-01, called
+- Linux Journal article by Michel J.Hammel, 2010-04-01, called
   [Mongoose: an Embeddable Web Server in C](http://www.linuxjournal.com/article/10680)