-add class for store Xref properties

-add widget for edit it
-make link betwen QET -> QETproject -> Diagram, for transmit the xrefproperties
-xrefpropertie can save/load to xml and setting.
-XRefItem don't use the properties yet


git-svn-id: svn+ssh://svn.tuxfamily.org/svnroot/qet/qet/trunk@2983 bfdf4180-ca20-0410-9c96-a3a8aa849046

sources/properties/propertiesinterface.h

@@ -0,0 +1,41 @@
+/*
+	Copyright 2006-2014 The QElectroTech Team
+	This file is part of QElectroTech.
+
+	QElectroTech is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 2 of the License, or
+	(at your option) any later version.
+
+	QElectroTech is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#ifndef PROPERTIESINTERFACE_H
+#define PROPERTIESINTERFACE_H
+
+#include <QString>
+#include <QSettings>
+#include <QDomElement>
+
+/**
+ * @brief The PropertiesInterface class
+ * This class is an interface for have common way to use properties in QElectroTech
+ */
+class PropertiesInterface
+{
+	public:
+	PropertiesInterface();
+	// Save/load properties to setting file. QString is use for prefix a word befor the name of each paramètre
+	virtual void toSettings	  (QSettings &settings, const QString = QString()) const =0;
+	virtual void fromSettings (const QSettings &settings, const QString = QString()) =0;
+	// Save/load properties to xml element
+	virtual void toXml		  (QDomElement &xml_element) const =0;
+	virtual void fromXml	  (const QDomElement &xml_element) =0;
+};
+
+#endif // PROPERTIESINTERFACE_H