Merge pull request #52 from ehmatthes/starting_classes

Started 'What are classes?'
Merge pull request #54 from ehmatthes/starting_classes

Starting classes
Merge pull request #55 from ehmatthes/starting_classes

Starting classes
Merge pull request #56 from ehmatthes/starting_classes

Starting classes
Merge pull request #57 from ehmatthes/starting_classes

Non-rocket exercises.
Merge pull request #58 from ehmatthes/starting_classes

Inheritance.
Enumerating a list.
Started section on imports.
Merge pull request #59 from ehmatthes/starting_classes

Exercise: Refining Shuttle.
Fixed merge conflict.
Added rocket.py module, updated .gitignore to ignore __pycache__.
Merge branch 'master', remote-tracking branch 'origin' into starting_classes
Storing multiple classes in a module.