Fixed #12, /fetchLast now supports a numerical parameter

In addition to the requirements listed in the ticket there was
an obvious improvement that could be made. Once you pull more than
one the order matters.

/fetchLast 3
  This will grab the last 3 items in the queue in the exact order they
  appear and push them to the front.
/fetchLast !3
  This will grab the last 3 items in the queue and will flip thier order
  which essentially emulate three successive /fetchLast calls.
Merge pull request #14 from Reanmachine/issue-12

Fixed #12, /fetchLast now supports a numerical parameter