Continuous play works now. Need to polish error handling.
Added first implementation of repeat and shuffle
More work on continuous play. Now works to run through playlist and if repeat, it repeeats. :)
More work
Fiixed continuous play and a few other bugs

* Fixed so that the queue can be played all the way. (Issue #7)
* Fixed skipping to next and previous songs in queue. (Issue #2)
* Regarding next and previous: this also makes sure that if repeat is
  on, the next and previous will wrap around and play the correct song,
* Now threading all the calls that can happen asynchronuously on the
  server. The only calls that are not threaded are the ones that require
  a reponse (such as show queue) (Issue #6)
* Added ability to shuffle current queue on server.
Merge branch 'master' into continuous-play