While the specification states that the "parameter" entity must always be defined---even if all model parameters are encoded within a single image, in which case value "all" must be used---two of the demonstrative examples did not obey such.

…er_entity

Resolves #52 (making "parameter" entity compulsory) against #51 (changing key for that parameter from "parameter" to "param").

Conflicts:
	src/05-derivatives/05-diffusion-derivatives.md