QETProject have is own database + add widget to edit nomenclature model

QETProject have is own ProjectDataBase, then when the database is
updated, everything that need the database is also updated trough the
signal emitted by the database.
Begin a widget to edit the NomenclatureModel

sources/dataBase/projectdatabase.h

@@ -23,9 +23,8 @@
 #include <QSqlQuery>
 #include <QPointer>
 
-#include "qetproject.h"
-
 class Element;
+class QETProject;
 
 /**
  * @brief The projectDataBase class
@@ -43,6 +42,10 @@ class projectDataBase : public QObject
 		virtual ~projectDataBase() override;
 
 		QVector<QStringList> elementsInfoFromQuery(const QString &query);
+		void updateDB();
+
+	signals:
+		void dataBaseUpdated();
 
 	private:
 		bool createDataBase();