Adds support for drb in server and client.

Still experimental at this stage
All tests working
Implements controlled asychrony via a worker

- This is much more sane than trying something complicated like
  celluloid
- Basically the worker is a thread that waits for something to be added
  to the queue, then runs that task
- There's only one worker, so tasks are performed in the order called
- Allows for a simple way to defer I/O calls. No need to worry about
  concurrency race conditions!
- All tests currently working
Add thread pool attribution
Removes Worker from task_engine.rb

- It was never supposed to be there anyway
delete_task now asychronous

Tests updated
Tasks now sorted

- Sorts tasks according to completion status
- Adapts task_server_test.rb to always find the "Test" tasklist
- Removes unsed code from task_server_test.rb