Render windows fps limit is slowing down the main thread

[Ovahlord]

So I got quite suspicious about the increddibly slow loading/saving and indexing times and after longer observation, it turns out that the render window is synchronous with the main thread and due to the hardcoded fps limit the whole thing is being slowed down by alot. It gets even worse once you actually start rendering anything inside of the render window.

So there are two solutions:

1. Unlock the fps of the render window and let the programm go nuts, which improves the loading and render fps by alot but also causes unnecessary load for the GPU
2. Make the rendering asynchronous, moving it to a 2nd thread, which should solve the problem alltogether

revision at the time of reporting: 8f06f75