Fix exit handlers for forks
Fix exit handlers for forks

We don't want to run our parent exit handlers but we do want to run any
exit handlers within the fork. By using exit!, no exit handlers were
run - even the good ones.
Now, we register a new exit handler to be run just before our parent
handlers are run. This handler exits without running the parent
handlers.

Grand Parent at_exit { run_once }
  Parent at_exit { run_once }
    Child at_exit { exit! # don't run inherited handlers }
      capybara's at_exit

Seedrs/specjour,sandro/specjour,salonlofts/specjour