Added interface BlockingDeque, and implementation for ExecutorCompletionService and LinkedBlockingQueue.
I had to implement a blocking queue for ExecutorCompletionService.  LinkedBlockingQueue could be very easily extended right now to implement the java 7 LinkedBlockingDeque.  Right now LinkedBlockingQueue just synchronizes and depends on LinkedList implementation.  But I wrote a very complete unit test suite so we if we want to put a more concurrent design here, we have a complete test suite to verify against.# Please enter the commit message for your changes. Lines starting
Added verify function to avoid throwing so many runtime exceptions in the tests
Merge pull request #195 from jentfoo/ExecutorCompletionService_and_LinkedBlockingQueue

Added interface BlockingDeque, and implementation for ExecutorCompletionService and LinkedBlockingQueue