plugins: Improve usability of iPod keymaps

- Reduce need to press multiple buttons at
the same time to quit a plugin

- Have "Menu" be default way to quit plugins or
to access plugin menu

- Fall back to (Long) "Select" or Long "Menu"
in cases where Menu button isn't available
(e.g. in ImageViewer and many games)

out of scope:
boomshine, lua_scripts, Rockpaint,
Doom, Duke3D, Pacbox, Quake,
Sgt-Puzzles, Wolf3D, XWorld,
Minesweeper, Pixel Painter, Spacerocks

Change-Id: I6d4dc7174695fe4b8ee9cbaccb21bdbfe6af5c48

manual/plugins/sokoban.tex

@@ -33,7 +33,7 @@ information about the level format, see
        \opt{HAVEREMOTEKEYMAP}{& }
     & Move the ``sokoban'' up, down, left, or right\\
 \opt{IRIVER_H100_PAD,IRIVER_H300_PAD}{\ButtonOff}
-\opt{IPOD_4G_PAD,IPOD_3G_PAD}{\ButtonSelect+\ButtonMenu}
+\opt{IPOD_4G_PAD,IPOD_3G_PAD}{Long \ButtonSelect}
 \opt{IAUDIO_X5_PAD,IRIVER_H10_PAD,GIGABEAT_PAD,MROBE100_PAD,SANSA_E200_PAD,SANSA_C200_PAD%
      ,SANSA_CLIP_PAD,SANSA_FUZEPLUS_PAD}{\ButtonPower}
 \opt{SANSA_FUZE_PAD}{Long \ButtonHome}