Topology tag

Introduced topology tag, like:

<topology level="domain"/>

<topology/> is informative only. It indicates at a user level how the mapping is configured for the location, be it one room per domain name, or one room per news article, etc.

Complete list of level-values:

• "multidomain": a room covers multiple domains or web sites
• "domain": a room for the top level internet domain
• "host": a room per host name
• "site": a room for the entire web site
• "category": a room per category of the web site
• "channel": a room per channel (e.g. a radio station's site)
• "thread": a room per thread (e.g. in a forum)
• "article": a room per article (e.g. a newspaper)
• "query": rooms are assigned depending on the URL-query
• "unique": each URL maps to a different room
• "language": a room per visitor language
• "selection": the room selection is on the web site
• "none": no room defined

See http://www.virtual-presence.org/notes/VPTN-2.txt