id en class of nav not set by default

[nweevers]

I think it's better not have a class or id by default. Just set the id or class when you need one.

Now when I don't need an id, I can't remove it. The html looks really ugly with an useless id property on the nav tag ;)

Thanks in advance for your new update :dancers:

[hubertprein]

Added in latest release.