[Base] Nav bar tweaks

    - Toggle on/off (CyanogenMod alredy did but only for hw keys devices). crDroid allow all devices to do that for those using PIE apps.
    - Nav bar dimensions (height and width)
    - Here we also automatically reverts CyanogenMod navbar toggle: https://github.com/crdroidandroid/android_frameworks_base/commit/b70cda7d0d9b5142f54d390275b5e2ffa64ae9b4

    PS: THIS COMMIT IS A SQUASHED PORTED FROM crDroid KK and 99% od the codes are from SlimRoms. I want to say a HUGE thanks to @kufikugel

(cherry picked from commit 539ffe5ea18583f142d5cf6ba4fd60a70ffb9da5)

Conflicts:
	packages/SettingsProvider/res/values/defaults.xml
	packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java
	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java
	services/core/java/com/android/server/wm/WindowManagerService.java

Change-Id: I88522228d4b038256bedec96cff1f8d598680615