Merging setup

This includes #61:

1.  Import history of the `setup` directory from the 'bc' repository.
2.  Move scripts into new location.
3.  Add link to instructions to `README.md`

To do:

1.  What default URL should the scripts print for setup instructions?  http://software-carpentry.org/setup/ no longer exists.
2.  What should be added to `README.md` to tell instructors that these scripts exist?