More useful permalinks

[roman-yagodin]

• Enable permalinks (but not full page info - tags, dates, user) for Edit skin - this will allow to provide permalinks for e.g. R7.News news entries.
• Add some text label to permalink formats (e.g. "Page", "Forum post", "News entry", etc.) to help user to understand context of permalink.
• Need a way to hide permalinks which is not applicable to the current context (e.g. by missing some required querystring params).
• Raw universal permalink based on full QueryString contents.