added optional option skipns for simplenavi call

[solewniczak]

Maybe it takes a bit of simplicity from this plugin but nevertheless it's very useful to me. I've added optional syntax for skipping namespaces in individual simplenavi instances. Syntax:
{{simplenavi>|skipns=pages to skip as in hidepages }}

The main reason for this modification is using simplenavi together with translation plugin to hide translation namespaces:
{{simplenavi>|skipns=en}}

[solewniczak]

What do you think about this feature?

[solewniczak]

Do you want to merge this feature into master?

[splitbrain]

The main reason for this modification is using simplenavi together with translation plugin to hide translation namespaces

Hmm, I assume you use it in a sidebar. Wouldn't it be easier to have sidebars in each translation namespace, each using simplenavi to only list the currently selected language?