[1/2] FB: Slim IME options

PS1: initial commit
- fb: add back all keyboard IME features back (1/2)
from: https://github.com/SlimRoms/frameworks_base/commit/d51b14e667fe0dfed02c5080fbea97c349a12889

 - ime switcher notification - thanks cm
 - slims fullscreen disable on landscape
 - slims force autorotation on IME
 - 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

PS2/3/4: fixes
Change-Id: I44e3a8f25216815adf9fb8393858274c456f0b97