lib8: implement more fastled 8 bit math as lib8 submodules

src/mappings.rs

@@ -1,6 +1,6 @@
 use crate::geometry::*;
 
-use crate::lib8::scale8;
+use crate::lib8::interpolate::scale8;
 
 use std::cmp::max;
 use std::fmt::{Formatter, Debug};