Restructure the src directory

It is split into
- /libgnucash (for the non-gui bits)
- /gnucash (for the gui)
- /common (misc source files used by both)
- /bindings (currently only holds python bindings)

This is the first step in restructuring the code. It will need much
more fine tuning later on.

libgnucash/backend/sql/gnc-sql-result.cpp

@@ -0,0 +1,48 @@
+/***********************************************************************\
+ * gnc-sql-result.cpp: Encapsulate the results of a SQL query.         *
+ *                                                                     *
+ * Copyright 2016 John Ralls <jralls@ceridwen.us>                      *
+ *                                                                     *
+ * This program 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.                 *
+ *                                                                     *
+ * This program 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 this program; if not, contact:                           *
+ *                                                                     *
+ * Free Software Foundation           Voice:  +1-617-542-5942          *
+ * 51 Franklin Street, Fifth Floor    Fax:    +1-617-542-2652          *
+ * Boston, MA  02110-1301,  USA       gnu@gnu.org                      *
+\***********************************************************************/
+
+extern "C"
+{
+#include <config.h>
+}
+#include <sstream>
+#include "gnc-sql-column-table-entry.hpp"
+
+#include "gnc-sql-result.hpp"
+
+GncSqlRow&
+GncSqlRow::operator++()
+{
+    auto& new_row =  m_iter->operator++();
+    if (new_row != *this)
+        m_iter = nullptr;
+    return new_row;
+}
+
+/*
+  GncSqlResult*
+  GncSqlRow::operator*()
+  {
+  return m_iter->operator*();
+  }
+*/