title: excel-builder(.js) is giving an error after opening generated file
body: <p>I'm generating an excel file with <a href="https://github.com/stephenliberty/excel-builder.js/tree/master" rel="nofollow noreferrer">excel-builder.js</a> like this:</p>
  
  <pre><code>    require([
      './js/LibrariesForXLSX/excel-builder',
      './js/LibrariesForXLSX/Excel/Table'
  ], function(builder, Table) {
      var book = builder.createWorkbook();
  
      //creating worksheets
  
      var userDataList = book.createWorksheet({
          name: 'mysheet'
      });
  
      //creating tables
      var userTable = new Table();
      userTable.setReferenceRange([1, 1], [2, userData.length]);
  
      //adding data and tables to sheets        
      userDataList.setData(userData);
      userDataList.addTable(userTable);
      //adding worksheets to workbook 
      book.addWorksheet(userDataList);
  
      //adding tables to workbook
      boook.addTable(userTable);
  
      //creating download data;
      var workBook = builder.createFile(book);
      var rawExcelData = "data:application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;base64," + workBook;
      var blob = exp_getBlob(workBook, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
  
      //downloading workbook
      saveAs(blob, 'export.xlsx');
  });
  }
  </code></pre>
  
  <p>where <code>userData</code> is a 2D javascript array like </p>
  
  <pre><code>['name', 'John Doe'
   'age', 23
  ]
  </code></pre>
  
  <p><code>saveAs</code> is a function from <code>fileSaver.js</code></p>
  
  <p>Everything works fine and the file is also generated, but when i try to open the file with <code>Microsoft Excel 2016</code> i get an error like: </p>
  
  <blockquote>
    <p>We found a problem with some content in 'export.xlsx'. Do you want us to try to recover as much as we can? If you trust the source of this workbook, click Yes.</p>
  </blockquote>
  
  <p>If i click yes everything is fine and the correct data shows up in the excel. <strong>Can i somehow get rid of this error message?</strong></p>