Port of Duke Nukem 3D

This ports Fabien Sanglard's Chocolate Duke to run on a version of SDL
for Rockbox.

Change-Id: I8f2c4c78af19de10c1633ed7bb7a997b43256dd9

apps/plugins/sdl/README

@@ -0,0 +1,51 @@
+See NOTES for Rockbox-specific porting notes.
+The original README is below:
+
+                         Simple DirectMedia Layer
+
+                                  (SDL)
+
+                                Version 1.2
+
+---
+http://www.libsdl.org/
+
+This is the Simple DirectMedia Layer, a general API that provides low
+level access to audio, keyboard, mouse, joystick, 3D hardware via OpenGL,
+and 2D framebuffer across multiple platforms.
+
+The current version supports Linux, Windows CE/95/98/ME/XP/Vista, BeOS,
+MacOS Classic, Mac OS X, FreeBSD, NetBSD, OpenBSD, BSD/OS, Solaris, IRIX,
+and QNX.  The code contains support for Dreamcast, Atari, AIX, OSF/Tru64,
+RISC OS, SymbianOS, Nintendo DS, and OS/2, but these are not officially
+supported.
+
+SDL is written in C, but works with C++ natively, and has bindings to
+several other languages, including Ada, C#, Eiffel, Erlang, Euphoria,
+Guile, Haskell, Java, Lisp, Lua, ML, Objective C, Pascal, Perl, PHP,
+Pike, Pliant, Python, Ruby, and Smalltalk.
+
+This library is distributed under GNU LGPL version 2, which can be
+found in the file  "COPYING".  This license allows you to use SDL
+freely in commercial programs as long as you link with the dynamic
+library.
+
+The best way to learn how to use SDL is to check out the header files in
+the "include" subdirectory and the programs in the "test" subdirectory.
+The header files and test programs are well commented and always up to date.
+More documentation is available in HTML format in "docs/index.html", and
+a documentation wiki is available online at:
+	http://www.libsdl.org/cgi/docwiki.cgi
+
+The test programs in the "test" subdirectory are in the public domain.
+
+Frequently asked questions are answered online:
+	http://www.libsdl.org/faq.php
+
+If you need help with the library, or just want to discuss SDL related
+issues, you can join the developers mailing list:
+	http://www.libsdl.org/mailing-list.php
+
+Enjoy!
+	Sam Lantinga				(slouken@libsdl.org)
+