Re: Remove some indirection layers

[Chris Warburton]

I've now done most of this refactoring. We have a 'runRacket' function
in Nix, which replaces the bash one-liners; this runs build scripts
written in Racket which replace the standalone scripts/*.rkt scripts, so
that the only remaining scripts are things which we'll actually call
from other projects (e.g. 'choose_sample').

Internally, I've done some refactoring of the cached values and things,
so that there should be less indirection.

The Racket code is certainly not optimal though ;)