Minor Pcbnew Python scripting improvement.

Added NETCLASSPTR constructor to swig interface. This enables scripts to
generate new net classes.

pcbnew/swig/netclass.i

@@ -1,3 +1,26 @@
+/*
+ * This program source code file is part of KiCad, a free EDA CAD application.
+ *
+ * Copyright (C) 2012 NBEE Embedded Systems, Miguel Angel Ajo <miguelangel@nbee.es>
+ * Copyright (C) 1992-2017 KiCad Developers, see AUTHORS.txt for contributors.
+ *
+ * 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, you may find one here:
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or you may search the http://www.gnu.org website for the version 2 license,
+ * or you may write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
 
 /*
 
@@ -25,6 +48,7 @@ function set if you see something missing from class NETCLASS that you need.
 %extend std::shared_ptr<NETCLASS>
 {
 public:
+    std::shared_ptr<NETCLASS>( std::string name )     { return new std::shared_ptr<NETCLASS>( new NETCLASS(name) ); }
 
     STRINGSET&  NetNames()                  { return (*self)->NetNames(); }