[2/2] Left handed navbar during landscape mode

This patch allows for the navbar to be moved to the left side of the
screen during landscape mode. Left handed people are more used to this
option.

Screenshot: http://i.imgur.com/jWqJcEV.png

Contributors:

Decad3nce
https://github.com/CyanogenMod/android_packages_apps_Settings/commit/a2b5ff1542e802f4257e7a7746ceb9e1c9cf333e

romanbb
https://github.com/CyanogenMod/android_packages_apps_Settings/commit/34344a5fa2a03d849901f09340f3dd8010e2a7fe

crpalmer
https://github.com/CyanogenMod/android_packages_apps_Settings/commit/6833e8c627e0b44b0ee7191fce714556ab3eac25

Change-Id: Ic95e3fda1f55efd2ec908c8d7226e638ec0ab80a

Conflicts:
	src/com/android/settings/ButtonSettings.java
Settings: fix NPE in ButtonSettings

Change-Id: Ib2ab4d7d5ed3aaceeba8fe942b7a29cd01f003fb