* chore(deprecation): add deprecation message to all methods that will be removed in v4 (#573)
* index.addObject(obj) --> index.addObjects([obj])
* index.ttAdapter --> autocomplete.js
* index.partialUpdateObject(obj) --> partialUpdateObjects([obj])
* index.saveObject(obj) --> index.saveObjects([obj])
* index.deleteObject(objectID) --> index.deleteObjects([objectID])
* index.getObject(objectID) --> index.getObjects([objectID])
* see https://github.com/algolia/algoliasearch-client-javascript/wiki/Deprecated for more information