Please create an AppData file for Chocolate Duke3D

[GreenLunar]

Please consider writing and installing an AppData file with the application description and some screenshots, else Chocolate Duke3D looks really bad in the GNOME and KDE Software Centers.

See http://people.freedesktop.org/~hughsient/appdata/ for details; thanks!

At the same opportunity, please generate a POT (localization template file) file to AppData and Desktop files.

Draft

<?xml version="1.0" encoding="UTF-8"?>
<!-- Copyright 2013-2016 Contributors to the Chocolate Duke3D project -->

<component type="desktop">
  <id>chocolate-duke3d.desktop</id>
  <metadata_license>LICENSE</metadata_license>
  <project_license>GPLv3</project_license>
  <developer_name>Fabien Sanglard, Juan Manuel Borges Caño</developer_name>
  <url type="homepage">http://fabiensanglard.net/duke3d/chocolate_duke_nukem_3D.php</url>
  <url type="bugtracker">https://github.com/fabiensanglard/chocolate_duke3D/issues</url>
  <description>
    <p>
      It’s time to kick ass and chew bubblegum... 
      and I’m all outta gum.
    </p>
    <p>
      Chocolate Duke Nukem 3D is a port of Duke Nukem 3D 
      aimed at education. The main goal is to clarify the 
      code so programmers can extract knowledge easily and 
      get a better idea of what it was to program game 
      engines in the 90s.
    </p>
    <p>
      Like an archeologist working on bones it was important 
      to keep things the way they were and only the "dust" 
      has been removed with focus on:
      <ul>
           <li>
               Readability : Make the code easy to understand.
           </li>
           <li>
               Portability : Make the code easy to compile, run and tinker with.
           </li>
      </ul>
    </p>
  </description>
  <screenshots>
    <screenshot type="default">
      <image>http://fd.fabiensanglard.net/duke3d/duke_top_roof.png</image>
      <caption>map_name: description.</caption>
    </screenshot>
    <screenshot>
      <image>http://fd.fabiensanglard.net/duke3d/duke_post_jump.png</image>
      <caption>map_name: description.</caption>
    </screenshot>
  </screenshots>
</component>