Added new osgGA - GUI Adapter library submitted by Neil Salter. This will

replace the current GUI adapter code inside osgUtil.

include/osgGA/GUIEventAdapter

@@ -0,0 +1,89 @@
+//C++ header - Open Scene Graph - Copyright (C) 1998-2001 Robert Osfield
+//Distributed under the terms of the GNU Library General Public License (LGPL)
+//as published by the Free Software Foundation.
+
+#ifndef OSGGA_GUIEVENTADAPTER
+#define OSGGA_GUIEVENTADAPTER 1 
+
+#include <osg/Referenced>
+#include <osgGA/Export>
+
+namespace osgGA{
+
+
+/** Pure virtual base class for adapting platform specific events into
+  * generic keyboard and mouse events. 
+  *
+  * Used as GUI toolkit independent input into the osgUtil::CameraManipualor's.
+  * For an example of how GUIEventAdapter is specialised for a particular GUI
+  * Toolkit see osgGLUT::GLUTEventAdapter.
+  */
+class GUIEventAdapter : public osg::Referenced
+{
+    public:
+
+        GUIEventAdapter() {}
+
+
+        enum MouseButtonMask { 
+            LEFT_MOUSE_BUTTON=1,
+            MIDDLE_MOUSE_BUTTON=2,
+            RIGHT_MOUSE_BUTTON=4
+        };
+
+        enum EventType {
+            PUSH,
+            RELEASE,
+            DRAG,
+            MOVE,
+            KEYBOARD,
+            FRAME,
+            RESIZE,
+            NONE
+        };
+
+        /** Get the EventType of the GUI event.*/
+        virtual EventType getEventType() const = 0;
+
+        /** key pressed, return -1 if inappropriate for this event. */
+        virtual int getKey() const = 0;
+
+        /** button pressed/released, return -1 if inappropriate for this event.*/
+        virtual int getButton() const = 0;
+
+        /** window minimum x. */
+        virtual int getXmin() const = 0;
+
+        /** window maximum x. */
+        virtual int getXmax() const = 0;
+
+        /** window minimum y. */
+        virtual int getYmin() const = 0;
+
+        /** window maximum y. */
+        virtual int getYmax() const = 0;
+
+        /** current mouse x position.*/
+        virtual int getX() const = 0;
+
+        /** current mouse y position.*/
+        virtual int getY() const = 0;
+
+        /** current mouse button state */
+        virtual unsigned int getButtonMask() const = 0;
+
+        /** time in seconds of event. */
+        virtual float time() const = 0;
+
+
+    protected:
+    
+        /** Force users to create on heap, so that multiple referencing is safe.*/
+        virtual ~GUIEventAdapter() {}
+
+};
+
+}
+
+#endif
+