Lifecycle events

[czyzby]

• [x] Lifecycle listeners support. Managed by LifecycleManager.
• [x] Dispose event on exit call.
• [x] Rendering loop.
• [x] Posting runnables.
• [x] Resizing events. Implemented both during fullscreen mode transitions and window size changes.
• [x] Pause and resume events. Should be called when application loses/gains focus.

[czyzby]

Implemented, needs to be tested.