lift: shorter file names
Now a compiler collection - Lift, Drift, & Crest. Remove kapreolo.
Beginnings of the new stage0 / backend / low-level lang
A collection of three compilers - Lift, Drift, and Crest - where each successive compiler is implemented in the language of the former, and all three compilers share the same bespoke backend (low-level IR and codegen).
From another perspective, Lift and Drift are the two bootstrapping stages of the main language of the collection - the high-level, functional programming language Crest.