spork should restart when a non-reloadable file changes

[alexch]

Spork loads the Rails environment, then forks. But sometimes the Rails environment changes (e.g. a change to environments/test.rb), leading to mistaken and irritating errors on the next test run. Spork should be smart enough to notice this and either gracefully exit or forcibly restart.

Guard-Spork and Rerun both noticed this problem and provide solutions, but it would be nice if Spork managed this on its own.

• https://github.com/guard/guard-spork
• https://github.com/alexch/rerun