unprepare hook: exitcode and throws error

[FelipeBarrosCruz]

Purpose: returns exitcode in unprepare hook and throws error if unprepare hook receive an error by param.

Scenario 1: I need to gracefully close some connections but someone returns an error, then pass by done callback in unprepare context the error.

Scenario 2: I need to get the Mocha assertion exit code to do some logic issue in unprepare context.

[QuentinFarizon]

I also would like my test process to fail if my un prepareHook fails.

Thanks @FelipeBarrosCruz, using your fork now, iot works fine ! :+1: