Make easy to add a checkbox preference

based from Cyanogenmod, but im adding more preferences :D
use SystemCheckBoxPreference if you want adding option for Settings.System
use SecureCheckBoxPreference if you want adding option for Settings.Secure
use GlobalCheckBoxPreference if you want adding option for Settings.Global

example:

we always using like this

    <CheckBoxPreference
        android:key="soft_back_kill_app"
        android:title="@string/soft_back_kill_app_title"
        android:summary="@string/soft_back_kill_app_summary"
        android:persistent="false"/>

and put preference into java code

but with this patch, we can use like this

    <org.omnirom.omnigears.preference.SystemCheckBoxPreference
        android:key="soft_back_kill_app_enable" << put key from android.provider.Settings
        android:title="@string/soft_back_kill_app_title"
        android:summary="@string/soft_back_kill_app_summary" />

the preference will always use presistent command

no need to add this preference into java code again :)
and say goodbye to bad java code style xD

Change-Id: I7da95d0db61c76ffcfc23c40dd711d322ac3bb29
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
Settings: Statusbar clock and date customizations (2/2)

Credits to slim

Change-Id: I0058a3e8c6ce229262113555b64c521fce34d6c4
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>