Application lifeTime and main loop.

[Shadowblitz16]

We need something to handle the lifetime of the ecs app and the ability to extend it.

Something like this for an api would be nice...

var runner = new Runner();
runner.Add(new DefaultPlugin())
runner.Run();

[Query]
private static void DefaultPlugin(in ICommandBuffer buffer)
{
     buffer.Add(new PrintSystem());

      var world = buffer.CreateWorld();
      var entity = world.CreateEntity(new Message("hi"))
      // Do something with entity?
}

[Query][All<Message>]
private static void PrintSystem(ref Message message)
{
    Console.WriteLine(message.Text);
}

I would even say rename QueryAttribute to SystemAttribute and have a PluginAttribute.

var runner = new Runner();
runner.Add(new DefaultPlugin())
runner.Run();

[Plugin]
private static void DefaultPlugin(in ICommandBuffer buffer)
{
     buffer.Add(new PrintSystem());

      var world = buffer.CreateWorld();
      var entity = world.CreateEntity(new Message("hi"))
      // Do something with entity?
}

[System][All<Message>]
private static void PrintSystem(ref Message message)
{
    Console.WriteLine(message.Text);
}

There does need to be a way to post a quit message to the Runner though.

[Shadowblitz16]

#285
#286
#287
#288