Added initial implementation of a rules Context class along with a ContextDefinition class and interface.
Added Rules variations of the ContextAwarePlugin base class and interface.
Added setters to the ContextDefinition interface and class.
Implement UserisBlocked condition based on RulesConditionBase.
Removed static contextDefinitions() from the interface.
Convert Node conditions to RulesConditionBase.
Merge pull request #27 from fago/feature/context

Issue #2245049: Added initial Rules variants of core context classes.