[Settings] 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)

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 4f8a4dc80e8bbb9493c053a93b814708a50d52a8)

Conflicts:
	res/values/cr_arrays.xml
	res/values/cr_strings.xml
	res/xml/button_settings.xml
	src/com/android/settings/ButtonSettings.java
Add option to Restart SystemUI to DevSettings

Change-Id: I1dd55510a878198f245ff90c011717ac5fb65f93
(cherry picked from commit af5179c220b037b2ff11bbd8a158818470977bfb)

Conflicts:
	res/values/cmr_strings.xml
	src/com/android/settings/DevelopmentSettings.java
Show wifi tab by default in Data Usage

On devices with cellular radios, the wifi tab is hidden by default.
This makes it visible.

Change-Id: Ie2f3a90c241e1e263e4b62f1a2995e001ae94328

(cherry picked from commit 385c02a73da4a3e7c3ae479a41387adfde8d379d)