Navbar, softkeys, NX, buttons, and action binding support (1 of 2)

-- Softkey long press and double tap actions
-- Softkey long press timeout
-- Persistent menu button (plays nice with IME picker too ;D)
-- NX 3.0a! The logo needs adaptation for LP icon style
   In fact, the entire logo implementation needs a overhaul
-- Action handler framework for binding events to actions
-- Constants and utils classes

Change-Id: I167db85f8eb73afb79d32371dc6b9f56738461ae