Feature Request: Light-weight `fluid.grid~` algorithm for faster transformations

[rconstanzo]

Following on from the discussion in this thread:
https://discourse.flucoma.org/t/cheap-and-cheerful-alternative-to-fluid-grid-for-larger-data-sets/

It would be great to have a light-weight/fast/cheap version of fluid.grid~ for working on larger datasets where speed is prioritized over effective distance computation.