Windows Explorer expects WAV LISTINFO chunk fields to to have trailing null

[IJabz]

Windows Explorer expects LISTINFO chunk fields to to have trailing null. Although other apps do not require this I think we should add the null char so displayed correctly in Windows Explorer, currently the last character of each field is not displayed.

Complicated by the fact that we don't want to add null character to fields in the ID3 chunk

[IJabz]

Fixed for most common scenarios, with updated tests