Fixes sound on most platforms, original root cause was bad menu code
as well as DMA callbacks taking too long. Worked around with smaller
chunk sizes. Permanent fix would include moving mixing out of the
callback. Rewrites input with code from rockboy/doom. Cherry-picks a
change from Gregory Montoir's `rawgl' to patch the code wheel
screen. Finally, adds a motion blur filter on select targets.

Change-Id: I8df549c923c5075800c6625c36c8202e53de1d27

XWorld grabs the audio buffer when it starts, so there can be no playback, making the playback control menu useless :P

Change-Id: Ia4e2c207f41619ef9b028917130d6dbf7dfba054

 - Comment keymaps.h
 - Tie XWORLD_DEBUG into ROCKBOX_HAS_LOGF to ease debugging
 - Fix up the manual a little bit

Change-Id: I12cfb58001199036cd67dbaa27f164e6790a199d
Reviewed-on: http://gerrit.rockbox.org/1084
Reviewed-by: Michael Giacomelli <giac2000@hotmail.com>

also fix a couple unused vars

Change-Id: Ib05d2e22dd7477bc9bd193232bd3de8a0816beb2
Reviewed-on: http://gerrit.rockbox.org/1079
Reviewed-by: Michael Giacomelli <giac2000@hotmail.com>

Co-conspirators: Franklin Wei, Benjamin Brown

--------------------------------------------------------------------
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

--------------------------------------------------------------------
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

--------------------------------------------------------------------
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.

--------------------------------------------------------------------
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>