Auto reload when other files than spec has been saved

[fvanwijk]

Currently the test runner reruns when you modify and save a spec file.

I like keep my code clean, so I move a lot of stuff to support files (by creating Commands). However, when I modify and save a support file, the tests are not re-running.

To extend this a bit, I also would like to auto reload when the src is changing (watching the baseUrl config parameter?).
Even better, a configuration parameter to set up a 'watch list' using globs would be awesome.

[jennifer-shehane]

Closing in favor of #456 which defines more specific implementation details.