Confidence Interval

Implemented methods for confidence intervals.
Subset

Added class Subset
Array implementation

Streamlined the bookkeeping. Chose array-based implementation.
Implemented sample()

Added the implementation for sample()
Implemented resize

Added the helper method resize(int)
Implemented dequeue

Added implementation for dequeue()
Fixed small name error. Implemented enqueue

Forgot to change old name repr to impl. Fixed that. Added the
implementation for enqueue.
Implemented RandomizedQueueIterator

Implemented RandomizedQueueIterator for the Queues iterator method.
Added annotations to deal with the Java monster.
Formatting changes

Added some formatting for beauty's sake.
Formatting, name error, reintroduced tail.

Added more formatting. Fixed yet one more naming error. Added back the
tail pointer as it IS crucial for the dequeue method.