allow actions to return its execution status.

[AntonioMeireles]

Hi,

Like what is already possible for 'Before' actions, i found useful and somewhat logical to have 'Actions' return something on exit, so that app.Run() gets to catch all errors, if any, underneath it. Please look at 52496bf in case you care.

All the best

[shinpei]

+1 for this pull request. Each Action could have same type of errors, and it'd be nice to handle them at once. Or any nice solution for this issue?

[kytrinyx]

This would be a significant breaking change, so I understand why @codegangsta would be hesitant to introduce it, even though the implementation is trivial. I've implemented the change and submitted a pull request so that if the change is desirable it can be pulled in.

[jszwedko]

Will try to get #66 in soon.