Added open-file by clicking on the filename in displayShow

Gives the user the possibility to choose an executable and enable the
function.
Once enabled the user can click on a filename of an episode in the
displayShow page to open the executable with the filename as a
parameter.
It should be extended to give the user the possibility to customize the
parameters given to the exec for broader compatibility.
Build on and tested with win8 and VLC, windows media player and mediaplayer classic.