* test: node v4 is now the default testing env
    * fix: always send a unique response to the user
    * fix: use `lodash` by default, only use `lodash-compat` when
    * building for the browser
    * feat: add client.addAlgoliaAgent() to augment the sent
    * x-algolia-agent
    * chore: move all deps to ^version and add a shrinkwrap to allow
    * reproducible builds