Switching over to slide-based materials
More content for Ruby lesson
Splitting up lessons, re-organizing
Added line about setting git editor
Use an editor to write commit messages instead of doing them at the command line
Better organization with one command per slide, added slide about history
Restored content lost from a bad merge
Moved some of the method and running a program material into the first lesson, added all OO examples into the second, removed individual code sample files because they are all part of one of the lessons now.
Fixed README to make new lesson names
Placeholder slide for some material on encapsulation.  Renamed Item to Product to avoid confusion with possible LineItem class
Added material for state and blocks