excel broken when create new file

[shawnye]

Description

Excel broken when create new file

Steps to reproduce the issue:

xlsx := excelize.NewFile()
xlsx.NewSheet("Sheet1")
xlsx.SaveAs("test.xlsx")

Describe the results you received:
Just trival process, but when open test.xlsx, excel 2013 compained:
发现部分内容有问题，是否让我们尽量尝试修复？

Describe the results you expected:
excel 2013 keep quilt as do before

Output of go version:

go version go1.9.2 windows/amd64

Excelize version or commit ID:

7621927       latest commit

Environment details (OS, Microsoft Excel™ version, physical, etc.):
window 7 professional, excel 2013

[xuri]

Thanks for your issue. When calling the NewFile() function will automatically create a worksheet named Sheet1, so we needn't call the function NewSheet() when only one worksheet in the workbook. Reference issue #185.

[shawnye]

Thank you!
I did not notice the example :<

xlsx := excelize.NewFile()
    // Create a new sheet.
    index := xlsx.NewSheet("**Sheet2**")