Problem: raco setup wants to compile files that are already compiled

[clacke]

This is most of the cause behind #38. Currently racket-doc cannot run raco setup, because it wants to recompile everything it touches.

This may be because it considers the compiled files not-newer than the source files. Maybe we need to patch setup or the compiler to accept equally-old files.

Or it may be because setup cannot find compiled files that aren't in the primary installation scope. This may be the same thing that made us want to symlink racket/share/racket/collects into the primary installation scope while setting up.