Updated to use BLPOP by default

* Revised Resque_Worker::work() and Resque_Worker::reserve()
* Made minor formatting changes for PSR-2 compliance
* Marked tests relying on interval 0 to stop a worker as incomplete
* Marked testBlockingListPop as incomplete
Added $workOnceThenShutdown param
Merge branch 'blpop-by-default' of https://github.com/zachgarwood/php-resque into blpop-by-default

Conflicts:
	lib/Resque/Worker.php

Conflicts:
	lib/Resque/Worker.php

Conflicts:
	lib/Resque/Worker.php