Navbar: improve button response time

reuse contexts instead of getting new ones
AwesomeAction: reduce obfustification on injectKeyDelayed
ACTION_HOME: remove injectKeyDelayed in favor of much faster IPC binder
inline some trivial method calls
keybuttonview: remove getter for ACTION_BLANK lookup
yatta yatta

Change-Id: Ia2b9c978f6dc241b70506fc104ac36782c7f74a9