Complete internal rewrite to remove stuttering and heavily improve performance

[Smartin-b]

-replaces scanntask with a asyncrounus ChunkCache -split bufferupload on a per chunk basis to remove stuttering

[MichaelHillcox]

Hay! I can't believe I haven't got back to you sooner… Firstly, thank you, this all looks amazing, this is what I have been intending to do for ages but never found the time.

Just a couple notes, and if you don't have time to address them, let me know and I'll sort it:

• No tooltip for the threads
• It would be great to still limit the chunks it scans. For a good amount of people, a smaller range is typically preferred, as it makes visibility easier.

That's it... I could be a perfectionist and ask for the newly generated sections of the render to fade in but that sounds too much like hard work.

Thanks again :+1: