Launch theme chooser that supports cyngn.intent.category.APP_THEMES

If we receive an ActivityNotFound exception we will simply show
the theme settings fragment.

Change-Id: I38bf6857125cdeda310e3bb5614fd6adaba8265f
Merge branch 'cm-11.0' of https://github.com/CyanogenMod/android_packages_apps_Settings into android-4.4_new