InCallUI: Landscape support (for in-dock use / qwerty sliders)

Change-Id: Ibce2c2c1c3fd3950f1191df6ea978fee151bd6ff
InCallUI: enable navbar while call is incoming

since we have back-button support to send incoming calls to
the statusbar, we need to make sure the navbar is actually enabled
while a call is incoming, otherwise that feature is totally unavailable
on devices that do not have hardware back button

Change-Id: Ibe58efadb06232baabca211078e14ba45360c298
InCallUI: Fix landscape layout

- http://review.cyanogenmod.org/65024 missed to do the button change
  also in landscape layout file, causing crash in landscape. Fixed.
- landscape layout updated according to the last 'qcril' merge
  (button order changed)

Change-Id: Ib75c7be432cc0f8ffc28c37d071ae18838cea26d