Added osgGA::Device class for integration of both physical and virtual devices.

Added template readFile(..) function to make it more convinient to cast to a specific object type.

Added support for osgGA::Device to osgViewer.

Added sdl plugin to provides very basic joystick osgGA::Device integration.

src/osgGA/Device.cpp

@@ -0,0 +1,31 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * 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
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include <osgGA/Device>
+
+using namespace osgGA;
+
+Device::Device()
+{
+    setEventQueue(new EventQueue);
+}
+
+Device::Device(const Device& es, const osg::CopyOp& copyop):
+    osg::Object(es,copyop)
+{
+    setEventQueue(new EventQueue);
+}
+
+Device::~Device()
+{
+}