"Implement" group symbolizer for SVG renderer.

Note that the "implementation" for SVG renderer is the same as
for other symbolizers there - i.e: empty.

include/mapnik/svg/output/svg_renderer.hpp

@@ -120,6 +120,9 @@ public:
     void process(debug_symbolizer const& /*sym*/,
                  mapnik::feature_impl & /*feature*/,
                  proj_transform const& /*prj_trans*/) {}
+    void process(group_symbolizer const& sym,
+                 mapnik::feature_impl & feature,
+                 proj_transform const& prj_trans);
 
     /*!
      * @brief Overload that process the whole set of symbolizers of a rule.

src/build.py

@@ -353,6 +353,7 @@ if env['SVG_RENDERER']: # svg backend
     svg/output/process_raster_symbolizer.cpp
     svg/output/process_shield_symbolizer.cpp
     svg/output/process_text_symbolizer.cpp
+    svg/output/process_group_symbolizer.cpp
     """)
     lib_env.Append(CPPDEFINES = '-DSVG_RENDERER')
     libmapnik_defines.append('-DSVG_RENDERER')

src/svg/output/process_group_symbolizer.cpp

@@ -0,0 +1,39 @@
+/*****************************************************************************
+ *
+ * This file is part of Mapnik (c++ mapping toolkit)
+ *
+ * Copyright (C) 2013 Artem Pavlenko
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ *****************************************************************************/
+
+// mapnik
+#include <mapnik/svg/output/svg_renderer.hpp>
+
+namespace mapnik
+{
+template <typename T>
+void svg_renderer<T>::process(group_symbolizer const& sym,
+                              mapnik::feature_impl & feature,
+                              proj_transform const& prj_trans)
+{
+    // nothing yet.
+}
+
+template void svg_renderer<std::ostream_iterator<char> >::process(group_symbolizer const& sym,
+                                                                  mapnik::feature_impl & feature,
+                                                                  proj_transform const& prj_trans);
+}