to address http://www.w3.org/2011/prov/track/issues/262 :
removed prov:qualified
added qualifiedUsage and friends (and corresponding domains and ranges)
made qualifiedUsage and friends inverse functional.
removed prov:Element b/c it isn't being used in domains and ranges anymore and is distracting
added prov:agent to complete the set with prov:entity and prov:activity
prov:agent domain AgentInvolvement, range Agent
added prov:qualifiedForm and prov:unqualifiedForm annotation properties.
renamed Annotation property involvementClass to qualifiedForm