Xworld - Another World interpreter for Rockbox

Co-conspirators: Franklin Wei, Benjamin Brown

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This work is based on:
- Fabien Sanglard's "Fabother World" based on
- Piotr Padkowski's newRaw interpreter which was based on
- Gregory Montoir's reverse engineering of
- Eric Chahi's assembly code

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Progress:

* The plugin runs pretty nicely (with sound!) on most color targets
* Keymaps for color LCD targets are complete
* The manual entry is finished
* Grayscale/monochrome support is NOT PLANNED
  - the game looks horrible in grayscale! :p

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Notes:

* The original game strings were built-in to the executable, and
  were copyrighted and could not be used.
* This port ships with an alternate set of strings by default, but
  can load the "official" strings from a file at runtime.

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To be done (in descending order of importance):

* vertical stride compatibility                          <30% done>
* optimization                                           <10% done>

Change-Id: I3155b0d97c2ac470cb8a2040f40d4139ddcebfa5
Reviewed-on: http://gerrit.rockbox.org/1077
Reviewed-by: Michael Giacomelli <giac2000@hotmail.com>

apps/plugins/xworld/README.rockbox

@@ -0,0 +1,51 @@
+This is the Rockbox port of Fabien Sanglard's "Fabother World", an Another World
+interpreter.
+
+Porting process:
+----------------
+
+The original code abstracted most of the platform-specific tasks, such as file I/O,
+sound, input, and video. However, the original code was in C++, so it was converted
+to C class-by-class. The conversion was attempted to be as conservative as possible,
+so little code was rewritten during the conversion process.
+
+Notes:
+------
+
+ - Optimization is badly needed.
+ - Vertical stride support is almost there.
+ - The game looks terrible in B+W/grayscale. This was the primary reason no attempt
+   was made to support these targets.
+ - The game does not run well on devices that have an LCD with a vertical stride.
+   - The M:Robe 500 is the only color device that meets this criterion, so it is
+     disabled by default.
+ - Sound doesn't sound 100% like the PC version. Perhaps the frequency reported to
+   the mixer is incorrect, or the buffer size is too big so that short sounds are
+   being missed.
+
+To do (in no particular order):
+-------------------------------
+
+ - Support vertical stride LCD's
+ - Support grayscale/monochrome LCD's
+ - Optimize
+
+Credits:
+--------
+
+**************************************
+**************************************
+********** !!!ERIC CHAHI!!! **********
+**************************************
+**************************************
+<the original author of Another World>
+
+Gregory Montoir
+Piotr Padkowski
+Fabien Sanglard
+
+Rockbox porters:
+----------------
+
+Franklin Wei
+Benjamin Brown