front: Implemented list-based input mapping screen for OUYA.

Supersedes the functionality provided in commit
393e6a7bd19ebb9549a96c0b6fd9ea4428206a7f
front: Added a preference to manually override OUYA mode.

Preference located in the Advanced menu.

Default value is 'auto', which just determines OUYA mode based on
hardware configuration.  OUYA users can use the standard interface if
they wish, and non-OUYA users can use the OUYA interface if they wish.
The latter case is an important one, not just for debugging the OUYA
version, but also for users who want to plug their phone/tablet into a
television and use only a gamepad for interaction.
bugfix: Fixed ListPreference summaries for pre-ICS devices.

Bug introduced in commit
59ca551bd27f1db09dca295c2e9f2c28b1da85bd

Android's documentation for ListPreference.getSummary is misleading, as
the string substitution feature was not introduced until API 14.
http://developer.android.com/reference/android/preference/ListPreference.html
cleanup: Fixed variable name for consistency.
front: Updated change log.