Session 4/5/6 Combined Pull

Accidentally wiped Session 4 branch before it could be merged on remote, but changes have been rolled forward into Session 5 branch.  New updates include Session 5 labs for testing, comprehension, and argument passing.
I think this is going to break is the user passes in a string to teh __init__, then wants to append more.

your __init__ should always create a list, so you know it's there.