Added file upload/download

mozen/src/main/java/mozen/auth/WebSecurity.java

mozen/src/main/java/mozen/business/IModelDao.java

mozen/src/main/java/mozen/business/IModelManager.java

mozen/src/main/java/mozen/business/ModelDao.java

mozen/src/main/java/mozen/business/ModelManager.java

mozen/src/main/java/mozen/model/CustomLayer.java

mozen/src/main/java/mozen/model/Model.java

mozen/src/main/java/mozen/utils/DatabaseFiller.java

mozen/src/main/java/mozen/web/ModelController.java

mozen/src/main/java/mozen/web/UserController.java