Generic EntityManager and extra model abstract superclass
Renamed to GenericTaskObserver
Added GenericEntityManager to ManagerLayer
Revert to default serialization for now, see if it works
Bugfixes and moving toJson into superclass
Merge branch 'generic-model' of https://github.com/slash-slash-no-comment-WPI-cs3733/wpi-suite into model

Conflicts:
	TaskManager/src/main/java/taskManager/model/GenericEntityManager.java
	TaskManager/src/main/java/taskManager/model/StageModel.java
	TaskManager/src/main/java/taskManager/model/TaskModel.java
	TaskManager/src/main/java/taskManager/model/WorkflowModel.java