add switchLanguage ComboBox in Settings to change app language. add option to disable lobby-chat. string update

src/gui/qt/settingsdialog/settingsdialogimpl.h

@@ -71,6 +71,8 @@ public slots:
 	void checkProperNetFirstSmallBlind(int);
 	void checkProperFirstSmallBlind(int);
 	void setFirstSmallBlindMargin() ;
+
+	void setLanguageChanged(int);
 	
 private:
 	
@@ -94,6 +96,9 @@ private:
 
 	QString myAppDataPath;
 
+	bool languageIsChanged;
+	int changedLanguageIndex;
+
 };
 
 #endif