Add sample hiera configuration
Add note about the module cache
Don't let .DS_Store files break script/bootstrap

Fixes boxen/our-boxen#512

In particular, I have seen problems with the following hidden files that Mac creates:
- `.DS_Store`
- `.!59508!.DS_Store`
- `.!59554!.DS_Store`
Merge pull request #555 from idris/patch-1

Don't let .DS_Store files break script/bootstrap
Mention the default hiera configuration in README
Suggest some example hierarchies
Be explicit that puppet-module-data is important
Merge pull request #552 from boxen/hiera-and-module-data

Hiera and module data
Fix typo for ripienaar/puppet-module-data module
Fix for when is GNU sed installed in homebrew with --default-names
Merge pull request #557 from stepanstipl/fix-puppet_module_data

Fix "Unable to find module 'ripienaa/puppet-module-data' on https://github.com"
Merge pull request #558 from stepanstipl/fix-gnu_sed

Fix for when is GNU sed installed in homebrew with --default-names
Update to puppet-nodejs 3.7.0
Merge pull request #559 from skottler/nodejs_370

Update to puppet-nodejs 3.7.0