Expand built-in rules

[nikku]

New rules

• [ ] bpmn:SubProcess must contain un-typed start events only
• [ ] bpmn:EventBasedSubProcess must contain typed start events only
• [ ] bpmn:Process should have only a single un-typed start event
• [ ] bpmn:Gateway should not be joining and forking at the same time
• [ ] bpmn:BoundaryEvent must have outgoing flows
• [ ] non bpmn:StartEvent flow nodes other than compensation activity and event based sub-processes must be connected (have incoming and outgoing flows)
• [ ] bpmn:InclusiveGateway should not be used
• [ ] bpmn:ComplexGateway should not be used
• [ ] bpmn:Event with multiple event definitions should not be used