Implemented simple show method inside Dequeue to hide unnecessary (large!) implementation detail from the client, in particular when using REPL
Fixed bugs related to Dequeue functions front and back. Front would give garbage data when called on a newly created queue, and back when popping a queue from the front. I've added additional tests to ensure consistency throughout. This would also produce erroneous behavior with Stack's top operation, which would give garbage data on a newly created stack.
Added 1 missing API call to the documentation
Merge pull request #1 from msainz/master

Fixed front/back bug inside Deque.jl, implemented simple show method, added additional tests, and added a missing API call to the documentation