go-ole: Most of the examples do not work.

Most of the examples do not work.

…/sample/excel/excel.go

panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x0 pc=0x4210e3]

goroutine 1 [running]:
ole.getIDsOfName(0x0, 0x3b1db8, 0x1, 0x1, 0xc0800000c8, ...)
    C:/Work/test/src/ole/idispatch.go:74 +0x163
ole.(*IDispatch).GetIDsOfName(0x0, 0x3b1db8, 0x1, 0x1, 0x0, ...)
    C:/Work/test/src/ole/idispatch.go:41 +0x81
ole/oleutil.PutProperty(0x0, 0x4bfdc0, 0x5, 0x3b1e48, 0x1, ...)
    C:/Work/test/src/ole/oleutil/oleutil.go:76 +0xb2
main.main()
    C:/Work/test/src/ole/example/excel/excel.go:18 +0x3b4
Error: process exited with code 2.