Materials should warn if the mesh does not satify its requirements

[shrinktofit]

I generated a line (through utils.createMesh with only positions and vertex colors) then rendered it with the standard effect. The use vertex color was enabled and the primitive mode was set to line. However the line was always rendered in white.

@jk20012001 indicates that meshes pass to standard effect should have normal correctly configured.

I wonder if it'd better warning on such mistake.

Test.zip

[SantyWang]

@star-e Please take look at this

[star-e]

Might be improved in 3.8.5.