Handle case with no lights on

With no lights we drop back to a shader that does not do lighting
equations, much like the 2D maper does by default. New valid image is
a 3D scene rendered without any lighting applied. Different than
the old backend which would still apply lighting equations just with
no lights. If you really want to generate that old style image, create a
light and set its color to black, or intensity to zero, etc. Having a
light that is on will cause the lighting equations to be used even if it
is black  (ZOMG you could have a black light)

Change-Id: I7a8aed9dd060b27528ab5746c4a0d2f3dfaa360a
Merge topic 'address_no_lights_on' into master

27f77f8c Handle case with no lights on