rem: status_t stop_layers_manager()
add: status_t stop_layers_manager(void)
context: status_t stop_layers_manager(){	net_layer *layer, *next;	const char *module_name;	delete_sem(g_layers.lock);	g_layers.lock = -1;	// TODO: handle multiple layers registered by same net module 	// disable all layers... 	layer = g_layers.first;	while (layer) {		next = layer->next;		module_name = layer->module->info.name;		dprintf("layers_manager: uniniting '%s' layer\n", layer->name);		// down the layer if currently up		layer->module->enable(layer, false);		layer->module->uninit(layer);		delete_layer(layer);		dprintf("layers_manager: unloading %s layer(s) module\n", module_name);		put_module(module_name);		layer = next;	};	puts("net layers manager stopped.");	return B_OK;}