XLSX.js is a JavaScript library for converting the data in base64 XLSX files into JavaScript objects - and back! Please note that this library is licensed under the Microsoft Office Extensible File License - a license NOT approved by the OSI. While this license is based off of the MS-PL, which is OSI-approved, there are significant differences.
This fixes issues where a browser had already loaded jszip.js but isn't using require. This also bumps the version to 2.3.1.