Sécurisation bean User
	modified:   database/Database.java
	modified:   database/sql/SQLDatabase.java
	new file:   exceptions/BeanException.java
	modified:   model/DataBean.java
	modified:   model/LoginManager.java
	modified:   model/User.java
	modified:   servlets/LoginServlet.java
	modified:   servlets/LogoutServlet.java
	modified:   servlets/TransactionServlet.java
	modified:   servlets/UserServlet.java
	modified:   utils/TransactionsUtils.java