Fixed Board.tile incorrectly returning hole instead of an empty tile
Correct entities are activated by various tiles

This approach does not work:
  for e in entities
    opts.afterHooks.push( => e.operation() )
It causes the operation() to be called several times on the
last entity.

Application should now pass all (7) tests :)
HTTP server does not use cache

Caching made debugging difficult because recent changes were
usually not sent to the browser.