Add set log level method and remove old, unused code (old destructor)

GeoModelIO/GeoModelDBManager/GeoModelDBManager/GMDBManager.h

@@ -56,8 +56,16 @@ class GMDBManager {
      * Close the db connection
      */
     ~GMDBManager();
-    void DestructorGMDBManagerStd();
-
+    
+     /// Set the 'loglevel', that is the level of output messages.
+    /// The loglevel is set to 0 by default, but it can be set
+    /// to a larger value.
+    /// Loglevel:
+    /// - 0 : Default
+    /// - 1 : Verbose
+    /// - 2 : Debug
+    void setLogLevel(unsigned loglevel) { m_loglevel = loglevel; };
+    
     bool initDB();
 
     int loadGeoNodeTypesAndBuildCache();
@@ -412,6 +420,9 @@ class GMDBManager {
        // verbosity level
        int m_verbose;
 
+       /// Stores the loglevel, the level of output messages
+       unsigned m_loglevel;
+
        /// stores the column names for each table
        std::unordered_map<std::string, std::vector<std::string>> m_tableNames;