-PageSize and PagesInBlock values can be adjust in runtime (at initialization time)

-added support for calling custon delegate function for all entities supported by selected system

tests/tests.d

@@ -501,6 +501,20 @@ struct TestSystem2
 
 }
 
+struct ExternalUpdateCallTest
+{
+	int print_count = 3;
+
+	void update(TestSystem2.EntitiesData data)
+	{
+		if(print_count > 0)
+		{
+			print_count--;
+			printf("ExternalUpdateCallTest %u %u\n", data.test[0].gg, cast(uint)data.length);
+		}
+	}
+}
+
 extern(C) int main()
 {
 
@@ -660,8 +674,6 @@ extern(C) int main()
 	gEM.registerSystem!TestSystem2(0);
 	gEM.endRegister();
 
-	System* sys = EntityManager.instance.getSystem(TestSystem2.system_id);
-
 	//gEM.generateDependencies();
 
 	//assert(*(cast(EntityID*)(cast(void*)tmpl.info.first_block+24)) == EntityID(1,1));
@@ -799,6 +811,12 @@ extern(C) int main()
 
 	gEM.commit();
 
+	System* sys = EntityManager.instance.getSystem(TestSystem2.system_id);
+
+	ExternalUpdateCallTest external_update_test;
+
+	EntityManager.instance.callEntitiesFunction!TestSystem2(&external_update_test.update);
+
 	printf("pre end\n");
 
 	writeEntityComponents(gEM.getEntity(entity));