* Make `time` private, having a `duration` and not actually breaking the build makes little sense
* Add note about usage in IRB
Add option to *not* exit when duration is exceeded, this is only used to clean up ugly `rescue SystemExit` in specs.
Add option to *not* output message when duration is exceeded, this is only used to clean up spec output.
Allow "outputter" (aka receiver of `puts`) to be stubbed in tests
move outputting of message from `exit_on_fail` in to its own method