Unignore the locale-data/ from npm package so its contents can be served

Currently the Bower package contains locale-data/ dir, and even though
the npm package contains `Intl.complete.js`, it's not practical to serve
because of its size. Including the locale-data/ dir makes it easier for
people to efficiently serve `Intl.min.js` along with a negotiated locale
resource pack.
Merge pull request #48 from ericf/npm-locale-data

Unignore the locale-data/ from npm package so its contents can be served