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
    <com.android.settings.liquid.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
picked from https://gerrit.omnirom.org/#/c/5759/7
	new file:   src/com/android/settings/liquid/GlobalCheckBoxPreference.java
	new file:   src/com/android/settings/liquid/SecureCheckBoxPreference.java
	new file:   src/com/android/settings/liquid/SystemCheckBoxPreference.java
Revert "Revert "Revert "Squash sidebar commits from ChaOS"""

This reverts commit 35b2294f3be4bcdd2ce48c2128a8304dfe07829e.

Conflicts:
	AndroidManifest.xml
	res/values/liquid_arrays.xml
	res/values/liquid_strings.xml
Revert "Status Bar Color [2/2]"

This reverts commit 0b20d8b5d444114819e6631c4ac32ff88bda9e33.

Conflicts:
	AndroidManifest.xml
	res/values/liquid_strings.xml
Revert "fix recents switcher"

This reverts commit b258d732d085b29c7c701e8461d5114b9345e49f.
Revert "SlimRecent: Make it optional [2/2]"

This reverts commit 055ed033b38fe30ee4243d02fcc82dad50dd02a4.

Conflicts:
	res/values/liquid_strings.xml