Tablets may be used in docking stations thus need to support landscape mode.
Phones will not be, and having them rotate is both ugly and annoying.
Also this matches lock screen behavior.
The attribute screenOrientation is not themeable, so the only way of doing
this is programmatic.
Test for truth of bool which is only set for sw600dp devices and
clear the nosensor setting from the manifest if set.
Bug: 16405551
Change-Id: I5b3f945b89402e5aa39642c2c06e98f9ca1ce298
Note: this entailed locking datetime settings not into portrait
like everything else in the setup process, but landscape, because
the existing xlarge layout wasn't rearranging itself into a portrait
alignment very well. I can give it another try later if I can have
some help from UE.
Change-Id: Ia8ce8e8292ed768bd117beedf3d94a287e658f4b
