Refactor mediator/crud to deal with errors cleanly, and add role support (wip)
Merge remote branch 'origin/master'

Conflicts:
	crud/src/main/java/com/redhat/lightblue/mediator/Mediator.java
	crud/src/main/java/com/redhat/lightblue/mediator/OperationContext.java
	mongo/crud/src/main/java/com/redhat/lightblue/crud/mongo/MongoCRUDController.java
	mongo/crud/src/test/java/com/redhat/lightblue/crud/mongo/CRUDControllerTest.java