Blue cube of 1 unit on each side, acting as placeholder for models failing to load

This model can be freely used by any Actor as placeholder or for debugging.

Property definitions

gamnit :: more_models $ Sys :: placeholder_model=
	# Blue cube of 1 unit on each side, acting as placeholder for models failing to load
	#
	# This model can be freely used by any `Actor` as placeholder or for debugging.
	var placeholder_model = new LeafModel(new Cube, new Material) is lazy
lib/gamnit/depth/more_models.nit:461,2--464,70