Add LOK Readme.
Allow setting DrawViewShell PageKind directly.

Currently the only way to change the PageKind is via the UI controls
(i.e. via ExecCtrl) -- however for tiled rendering we want to select
the PageKind directly.

Change-Id: I3a3fa8f8cefaa0e0212832aef4026433fc596263
Render slides by default.

We should probably introduce an API to allow selecting notes instead, however
the default mode is to open whichever view we had open last for a given
document -- whereas for nowwe probably always want to render the slides.

Change-Id: I26540613d1a510f23e5abfc8fee2ad743c180f34