Base: Add back all keyboard IME features back (1/2) and Volume rocker: Option to control cursor in text fields (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

Change-Id: I4242a67f88cfd63f20744fc5b398700cf5697644