Log Message:
Update ruby-parallel to 1.9.0.

v1.7.0 -- Mar 26, 2016

* Added an SQLite case
* Made adjustments to the SQLite case file as per @grosser's suggestions.
* Broke the SQLite tests out by worker_type like the other .each tests.
* support true in progress

v1.8.0 -- Mar 27, 2016

* isolation
* fix sqlite specs
* stderr output is a failure reason

v1.9.0 -- Jun 01, 2016

* expose parallel_worker_number via thread local so tasks can coordinate
  external dependencies
* also set parallel_worker_number when working directly
* more localized worker number setting for in_threads
* use .worker_number instead of direct thread var access
* add stderr redirection to spec case file invocation