Make default immersive mode style be the stock immersive mode style

Change-Id: Idc04d196725f5b305b9170b42a2ffe92a8f9c452
Enable nav bar for devices with hardware keys

Based loosely on the similarly-named change by Brandon McAnsh <brandon.mcansh@gmail.com>

... hehe... I said "loose".

ps2: give it the nuclear treatment
ps8: handle SearchPanelSwipeView while handling navbar wantingness

Signed-off-by: nuclearmistake <nuclearmistake@gmail.com>
Change-Id: I2704e99571deff62523da8113971096f79d14fc9
Merge remote-tracking branch 'upstream/kk44' into kk44