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

apps/plugins/codebuster.c

@@ -438,6 +438,13 @@ enum plugin_status plugin_start(const void* parameter) {
                 if (button == PLA_SELECT)
                     break;
 
+#if (CONFIG_KEYPAD == IPOD_1G2G_PAD) \
+    || (CONFIG_KEYPAD == IPOD_3G_PAD) \
+    || (CONFIG_KEYPAD == IPOD_4G_PAD)
+                if (button == PLA_UP) /* Menu button */
+                    button = PLA_CANCEL;
+#endif
+
                 switch (button) {
 
                     /* Exit */