Attach events to scenes

Currently a scene can support theses events:

• Key pressed: event_key_pressed
• Mouse pressed: event_mouse_pressed
• Mouse released: event_mouse_released
• Mouse moved: event_mouse_moved
• Mouse wheel scrolled: event_mouse_wheel_scrolled
• Text entered: event_text_entered
• Tick: event_tick
• Scene initialization: event_init
• Scene initialization post: event_init_post

To attach an event to a scene you will have to create a function with the name you want but with the required argument.
In this example we will attach a key press event.

void key_press_event(bs_event_key_pressed_t event)
{
	bs_frame_t *frame = event.frame;

	if (event.event.code == sfKeyEscape) {
		sfRenderWindow_close(frame->window);
	}
}

scene->event_key_pressed = &key_press_event;