fb: add back all keyboard IME features back (1/2)

this commit adds:

- ime switcher notification - thanks cm
- slims fullscreen disable on landscape
- slims force autorotation on IME
- volume button control for navigate in the message - thanks cm
- slims force to show always enter key

some fixes to the 4.2/4.3 implementations + added full multiuser
support for all this features

cheers

Change-Id: I71e93c39620cc171e658b2d7e26491bac97c651d

Conflicts:

	core/java/android/inputmethodservice/InputMethodService.java
	core/java/com/android/internal/statusbar/IStatusBar.aidl
	core/java/com/android/internal/statusbar/IStatusBarService.aidl
	core/res/res/values/slim_symbols.xml
	packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java
	services/java/com/android/server/InputMethodManagerService.java
	services/java/com/android/server/StatusBarManagerService.java

(cherry picked from commit 39d6ff22b743383fca17b6874bdd3254f73d9407)