Update backbone-indexeddb.js
Update backbone-indexeddb.js

Scope _ and Backbone variables using the 'var' keyword. If exports is undefined, then get them from the 'window' object explicitly.
superfeedr/indexeddb-backbonejs-adapter,zawaideh/indexeddb-backbonejs-adapter,zawaideh/indexeddb-backbonejs-adapter,superfeedr/indexeddb-backbonejs-adapter