anchor.diff:  -spec create_entity(Behavior::atom(), Definition::json()) ->
   	{ok, Entity::#entity{}} | {failed, Reason :: string()} | {error, Msg :: string()}.
   
  -create_entity(_Behavior, _Definition) ->
  -	{failed, "Not implemented."}.
  +create_entity(Behavior, Definition) ->
  +	Entity = #entity {
  +		behavior = Behavior,
  +		definition = Definition,
  +
  +		%TODO: What's a good default to use for model? undefined?
  +		model = proplists:get_value(<<"model">>, Definition, [{model, <<"Ships/ares">>}])
  +	},
  +
  +	% Get the best entity engine to send this entity to, and then add it.
  +	EnginePid = gen_server:call(pre_entity_engine_sup, {get_best_engine, Entity}),
  +	pre_entity_engine:add_entity(EnginePid, Entity).
   
   %% --------------------------------------------------------------------------------------------------------------------
   
  
positive.code: -spec get_entity(EntityID :: binary()) ->
  	{ok, Entity :: #entity{}} | not_found | {error, Msg :: string()}.
  
  get_entity(_EntityID) ->
  	{error, "Not implemented."}.
  
  %% --------------------------------------------------------------------------------------------------------------------
  
  
negative.code: 	(Behavior::atom(), Definition::json(), EntityEngine::pid()) ->
  		{ok, Entity::#entity{}} | {failed, Reason :: string()} | {error, Msg :: string()}.
  
  create_entity(Behavior, Definition, ClientInfo=#client_info{}) ->
  	Entity = #entity {
  		behavior = Behavior,
  		definition = Definition,
  		client = ClientInfo,
  
  		%TODO: What's a good default to use for model? undefined?
  		model = proplists:get_value(<<"model">>, Definition, [{model, <<"Ships/ares">>}])
  	},
  
  	% Get the best entity engine to send this entity to, and then add it.
  	EnginePid = gen_server:call(pre_entity_engine_sup, {get_best_engine, Entity}),
  	pre_entity_engine:add_entity(EnginePid, Entity);
  
  create_entity(Behavior, Definition, EntityEngine) ->
  	Entity = #entity {
  		behavior = Behavior,
  		definition = Definition,
  
  		%TODO: What's a good default to use for model? undefined?
  		model = proplists:get_value(<<"model">>, Definition, [{model, <<"Ships/ares">>}])
  	},
  
  	% Add this to the specified entity engine.
  	pre_entity_engine:add_entity(EntityEngine, Entity).
  
  %% --------------------------------------------------------------------------------------------------------------------
  
  