Index mentity so it can be retrieved by a find query

MEntities are indexed by both name and full_name.

Property definitions

nitc $ ModelIndex :: index
	# Index `mentity` so it can be retrieved by a find query
	#
	# MEntities are indexed by both name and full_name.
	fun index(mentity: MEntity) do
		mentities.add mentity
		index_by_name mentity
		index_by_full_name mentity
	end
src/model/model_index.nit:316,2--323,4