Fix for Issue #30

[pauljamesrussell]

This is a fix for issue #30. I've implemented the following changes as discussed in the issue. Feel free to cherry pick, but please bear in mind that some of the commits are bug fixes on earlier commits (sorry!).

• Changed the default :wait option to 30 seconds, and updated documentation accordingly.
• Implemented a 60 second 'grace period' after the wait period has expired.
• Updated error messages and notifications as appropriate, including telling the user how long it actually took to start spork and recommending updating the :wait option accordingly.
• Implemented a spec for this behaviour (there was no spec at all originally). Note that coverage is not 100% - I haven't implemented a spec for the retry loop itself, although its implicitly tested to some degree in the success scenarios.
• Implemented a tweak to the specs to make them run faster by stubbing a 'virtual' sleep method into the runner which does a no-op.

Thanks,

Paul

[thibaudgg]

Thanks!