Tweaked the tutorial.
Finished everything I can think of to say about Main in the tutorial.
Fixed tutorial-8, which was setting the number of capabilities to 2.

There is no point in doing this since the user is allowed
to continually change the number of workers, and
unforutnately calling setNumCapabilities too often
destabilizes the runtime.
Fixed word-wrapping in TUTORIAL.md
Tweaked the description of Threads in TUTORIAL.
Wrapped up TUTORIAL.md with a brief conclusion.
Fixed up and finished section on running program in parallel in USERS_GUIDE.md
Exposed begin/endSupervisorOccupied.
Finished the Users' Guide!