[FEATURE] Drop '/index' from generated URLs

The default URLs that are generated for a page include '/index' at the end if the underlying file is called 'index.md'. In my opinion, this is unnecessary and ugly. I'd rather have a link called '/projects' than a link called '/projects/index'. Both would result in the same page anyway, so it's safe to drop them here for cosmetic reasons.
agree, buildUrl must be protected, public access should only be possible with getUrl()