Fixed Direct3D 11 depth buffer creation

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
Added automatic D3D11 backbuffer resize

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
Added D3D11 drawing loop sample

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
Updated documentation

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>