front: Remove a few big-screen-mode customizations.

The volume button mappability should still be selectable since the
M.O.J.O controller has volume buttons on it.  Plus there's no need to
be so heavy handed.  The touchscreen stuff can also stay since we'll
be moving it out of the global settings soon anyhow.
front: Pull profile implementation up to base classes, reduce generics.

Other profile types will be sharing most of the same code.
cleanup: Rename *ProfileActivity -> Manage*ProfilesActivity.

Reserve the name *ProfileActivity for future classes that will parallel
PreferenceActivity.
cleanup: Rename *ProfileEditActivity -> *ProfileActivity.

These classes will parallel the PreferenceActivity class in purpose and
implementation.
front: Make controller profile fields on-demand rather than cached.

This is more flexible and doesn't require us to refresh (replace)
profile instances every time we change a field value.  Also keeps the
constructors maintainable.

Also eliminate the read and write methods, using the base class methods
and constructors instead.
front: Modularize some code in PlayMenuActivity.
front: Extend CheckBoxPreference to persist to string (not boolean).

Needed for compatibility with future ProfileActivity class.
front: Extend SeekBarPreference to persist to string (not int).

Needed for compatibility with future ProfileActivity class.
front: Add base class for PreferenceActivity-like profile editors.

Add an abstract base class for implementing simple list-based profile
editor activities. This class is meant to be subclassed the same way
that a PreferenceActivity would be, and the process for defining the
structure and behavior is virtually identical. That is, the hierarch-
ical menu structure and default values are defined using an xml re-
source, using identical syntax to that used for a PreferenceActivity.
Similarly, the behavior of the activity (lifecycle, inflation, menu
visibility, change notifications, etc.) is implemented just as it would
be for a PreferenceActivity. It is thus trivial to migrate implementa-
tion between a PreferenceActivity (backed by a SharedPreferences
object) and a ProfileActivity (backed by a ConfigSection object).

The one important caveat is that this class persists all settings as
Strings. This means that some of the standard Preference classes must
be extended a bit. For example, the CheckBoxPreference class persists
to boolean. Therefore, to make a checkbox-style preference that works
with ProfileActivity, extend CheckBoxPreference and override the
persistBoolean and getPersistedBoolean methods.
front: Add emulation profiles implementation.
front: Add touchscreen profiles implementation.
cleanup: Make UserPrefs.Plugin a top-level class.
front: Expose controller share mode in UserPrefs.java.
front: Pass MD5 to game activities and read extras bundle sooner.
front: Split GamePrefs out of UserPrefs (global prefs).
front: Remove global video/touchscreen settings (per-game now).