[pmwiki-users] updated notebook-nt - minor changes

[V.Krishn]

Just updated notebook-nt skin
Changes:
- minor css changes
- adjusted copyright notices.

Pm, Hans
Sorry for mistakingly removing the copyright notice from default css. I just 
copied and pasted from my old notebook skin template.

Pm, could we have a page, kinda help note for contributors who are creating 
new work or derivatives of existing work along with some sample how to 
preserve the notices, specially if its a derivative work.
Pm could you pls update skin as this is important copyright wise.
Please feel free to adjust the notice as top of default.css accordingly.

Thanks a lot
V.Krishn