Currently the EnhancementEngines can only retrieve the merged view over all Enhancement Properties (as defined by
STANBOL-488). This includes the "chain scoped" properties - defined by the Enhancement Chain configuration as well as the "request scoped" properties - defined for a single enhancement request.
This is required for implementing EnhancementEngines that only want to react of properties provided by Chain configuration but to not want to allow overriding those by Enhancement Requests (e.g. the configuration of an external service endpoint or user/pwd for an external service).