Adding a test for multithreaded objects.  Had to start adding throws
BackoutExceptions to several methods and sew them throughout the code.
Checks full life cycle of create, write, read, commit multithreaded number variable.
Updated multithreaded test to actually perform concurrent reads on the same variable.
Commit does two things:
  1) Adds threadpool class.

  2) Added a test to ensure that a read waits to acquire lock after
     write holding lock with higher priority.
Added a test for preempting events.  It currently fails.