Issue reading MulBlank record

[kleeon]

OpenFile panics for some documents with this message:

panic: runtime error: slice bounds out of range [:960] with capacity 958

goroutine 1 [running]:
github.com/shakinm/xlsReader/xls/record.(*MulBlank).Read(0xc000076ce0, {0xc000a92c8d, 0xc00705eac8?, 0x4?})
C:/Users/####/go/pkg/mod/github.com/shakinm/xls!reader@v0.9.11/xls/record/mulblank.go:61 +0x1fc
github.com/shakinm/xlsReader/xls.(*Sheet).read(0xc0000b81b0, {0xc000820000, 0x27304b?, 0x27304b})
C:/Users/####/go/pkg/mod/github.com/shakinm/xls!reader@v0.9.11/xls/sheet.go:194 +0xf9e
github.com/shakinm/xlsReader/xls.readStream({0x10f28c8, 0xc0000704b0}, 0x27304b)
C:/Users/####/go/pkg/mod/github.com/shakinm/xls!reader@v0.9.11/xls/xls.go:99 +0x1a5
github.com/shakinm/xlsReader/xls.openCfb({{{0xd0, 0xcf, 0x11, 0xe0, 0xa1, 0xb1, 0x1a, 0xe1}, {0x0, 0x0, ...}, ...}, ...})
C:/Users/####/go/pkg/mod/github.com/shakinm/xls!reader@v0.9.11/xls/xls.go:65 +0x1df
github.com/shakinm/xlsReader/xls.OpenFile({0x10ce961?, 0xc000036000?})
C:/Users/####/go/pkg/mod/github.com/shakinm/xls!reader@v0.9.11/xls/xls.go:20 +0x185
main.main()
C:/Users/####/Desktop/projects/excel_xml/main.go:98 +0x33
exit status 2

I tracked down the issue to this line:

xlsReader/xls/record/mulblank.go

Line 59 in 4c7ea4f

sPoint := 4 + (i * 6)

According to Microsoft docs, IXFCell structure is 2 bytes long, not 6. So the indexing seems to be off