newfairs-v3 is the container project. newfairs-core is a package.
meteor create newfairs-v3
cd newfairs-v3
meteor create --package newfairscommerce:core
cp -r ../newfairs-core packages
mv packages/core/{package.js,README.md} packages/newfairs-core/
rm -rf package/core
meteor add newfairscommerce:core
Then you have to define dependencies for this package with adding some
api.use() and loading order by adding some api.addFiles(...)
in packages/newfairs-core/package.js.