Split the `games` collection out of the main repository.

The `games` collection is now at
  https://github.com/racket/games

original commit: 9b934780980a6b9ce729436977f928f740cf01a8
Split `slatex` from the main repository.

Source for `slatex` is now available from:
  https://github.com/racket/slatex/

original commit: fe934dfe8956e9077c8677cd453af85e7c7406a4
Split `eopl`, `preprocessor`, and `make` from the repository.

They are available at:
  https://github.com/racket/eopl
  https://github.com/racket/preprocessor
  https://github.com/racket/make

original commit: bf5ec036f2cd4d7118f7fe07f1a9f9932c1cf18b
Split `picturing-programs` and `swindle` from the main repository.

They are available at:
  https://github.com/racket/picturing-programs
  https://github.com/racket/swindle

original commit: 3d0e2ad5cda930693e57d547f3691aff8bf977ed
Split `frtime` from the main repository.

Source for `frtime` is now at:
  https://github.com/racket/frtime/

original commit: 883a072e278df1cfb3969a678098ebef3a76f52e
Remove extra directories.