Fix of EVENTS type parsing from JSON response

Current version of Java SDK doesn't parse Events service response correctly. As result request to this endpoint leads to NPE in older drivers and in the version 2.1.2 (latest) it results to the following exception:
```
java.lang.ClassCastException: com.box.boxjavalibv2.dao.BoxTypedObject cannot be cast to com.box.boxjavalibv2.dao.BoxEventCollection
	at com.box.boxjavalibv2.resourcemanagers.BoxEventsManager.getEvents(BoxEventsManager.java:65) ~[BoxJavaLibraryV2-2.1.2.jar:na]
```

The fix is simple: need add correct mapping for BoxResourceType.EVENTS to BoxResourceHub.getObjectClassGivenConcreteIBoxType(IBoxType) method.