Changes made for the San Francisco workshop - for team review

Main changes:

* Break up data types (in intro portion), data structures, and functions and interleave them to create better flow across the morning
* Update all the examples to be based on real world situations (calculating tax, restaurants and menu items etc)

Note that we have updated the slides but *not* the gh-pages branch as we have been unable to figure out how to re-generate the finished slide deck (and there are no instructions for this in the repo).