ability to autoplay ACTION_LAUNCH links
 - needs a line in the rc file as
   "key Right = action auto"
   this autoplays the video when the right arrow key is pressed on
   a slide that contains and ACTION_LAUNCH link.
 - minor cleanup of link params handling
   now, the additional coordinaes are appended after handling the NULL case
Merge pull request #15 from iffsid/master

ability to autoplay ACTION_LAUNCH links