Lulu fixes and improvements

[pjpei]

Hi!

Thank you for considering this pull request!

I updated the LULU filter in the following ways:

1. Changed the indentation to K&R with 4 spaces instead of tabs.
2. Updated the interpretation to seemingly perform better at high throttle.
3. Updated to have a proper fixed delay instead of quasi-variable delay.

I believe this is a better filter for higher throttle compared to the previous.

Let me know if I should change anything or fix anything!