Add methods to receive asynchronous output from parallelizer
- make parallelizer less eager to process inputs on its thread except when unblocking, to leave it free to send outputs
- allow parallelizer to start making headway with long-running inputs before the inputs are done
- use ruby internal Queues to manage locking instead of mutexes
Add parallel_do method for when you don't care about output
Add :stop_on_exception to stop consuming input on exception
Add each_with_exceptions to allow all results to be known
Add ability to flatten parallel enumerable
Make it possible to resize and gently stop the parallelizer
Make parallel enumerable safe to restart
Prevent parallel first/take/drop from processing things it shouldn't
Do not provide "lazy" unless it is available (Ruby 2.0+)
Fix tests on 1.8.7
Remove unneeded requires when using CookbookVersionLoader

CookbookVersion and CookbookVersionLoader may interact with classes
defined in these files, but never reference their constants directly, so
they do not need to be loaded.
Merge parallelizer robustification and enhancements
Turn off bad test on Solaris