Merge origin/brach_for_push

Conflicts:
	build.xml
	nbproject/build-impl.xml
	nbproject/genfiles.properties
	nbproject/project.properties
	nbproject/project.xml
	src/controller/CommunicationController.java
	src/controller/Controller.java
	src/db/DbManager.java
	src/db/DbManager0.java
	src/model/Messaggio.java
	src/model/Proposta.java
	src/model/SistemaCifratura.java
	src/model/Studente.java
	src/model/UserInfo.java
	src/view/Registrazione.java