import history of setup/ from bc repo

As discussed in #1, here is the history of the setup/ folder from swcarpentry/bc.  I think it will be easier to merge the history of index.html in a separate PR, unless someone can tell me otherwise. 

For reference, I loosely followed [this](http://stackoverflow.com/questions/359424/detach-subdirectory-into-separate-git-repository/17864475#17864475) and [this](http://stackoverflow.com/questions/2314652/is-it-possible-to-move-rename-files-in-git-and-maintain-their-history) to extract the history from the bc repo and prepare it for import. Specifically: 

```bash
git clone https://github.com/swcarpentry/bc
cd bc

# split the history of setup/ into the setup-history branch
git subtree split -P setup -b setup-history
git checkout setup-history

# all of the files from setup/ are now in the root, so we need to move them into setup/
# before import
git filter-branch --tree-filter 'mkdir -p setup; mv * setup || true;' HEAD

# now pull into workshop-template
cd ..
git clone git@github.com:pipitone/workshop-template
cd workshop-template
git checkout -b pr-import-bc-setup-history
git pull ../bc setup
```